Intraband Auger effect in InAs/InGaAlAs/InP quantum dot structures
T. Gebhard, D. Alvarenga, P. L. Souza, P. S. S. Guimaraes, K. Unterrainer et al.
InAs quantum dot structures grown on InGaAlAs have been investigated for midinfrared photodetection. Intraband photocurrent and absorption measurements, together with a full three-dimensional theoretical modeling revealed that a bound-to-bound optical transition, where the final state is about 200 ... [Appl. Phys. Lett. 93, 052103 (2008)] published Thu Aug 7, 2008.
Electron mobility in phosphorous doped {111} homoepitaxial diamond
J. Pernot and S. Koizumi
The room temperature Hall electron mobility of phosphorous doped {111} homoepitaxial diamond is investigated experimentally and described theoretically for different doping and compensating center densities. The impurities mobility dependence is established. The mobility is found to be controlled by ... [Appl. Phys. Lett. 93, 052105 (2008)] published Thu Aug 7, 2008.
Band alignment and thermal stability of HfO[sub 2] gate dielectric on SiC
Q. Chen, Y. P. Feng, J. W. Chai, Z. Zhang, J. S. Pan et al.
The band alignment and thermal stability for HfO films on SiC with and without nitridation have been studied by using photoemission spectroscopy. The valence- and conduction-band offsets at HfO/4H-SiC interfaces were measured to be 1.02 and 1.53 eV, respectively. The atomic source nitridation improv ... [Appl. Phys. Lett. 93, 052104 (2008)] published Thu Aug 7, 2008.
Publisher's Note: Maximally localized Wannier functions within the FLAPW formalism [Phys. Rev. B [bold 78], 035120 (2008)]
F. Freimuth, Y. Mokrousov, D. Wortmann, S. Heinze, and S. Blugel
... [Phys. Rev. B 78, 089902 (2008)] published Thu Aug 7, 2008.
Contribution of the second Landau level to the exchange energy of the three-dimensional electron gas in a high magnetic field
J. M. Morbec and K. Capelle
We derive a closed analytical expression for the exchange energy of the three-dimensional interacting electron gas in strong magnetic fields, which goes beyond the quantum limit (L=0) by explicitly including the effect of the second, L=1, Landau level and arbitrary spin polarization. The inclusion o ... [Phys. Rev. B 78, 085107 (2008)] published Thu Aug 7, 2008.
Determination of the interface states in GaAs MOS diodes by deep-level transient spectroscopy
Kimiyoshi Yamasaki and Takuo Sugano
The capture cross sections and density-energy distribution of the trap states at the interface between GaAs epitaxial layers and oxide films grown by anodization in oxygen plasma have been determined by deep-level transient spectroscopy (DLTS). The capture cross sections are of the order of 1010 cm. ... [Appl. Phys. Lett. 35, 932 (2008)] published Thu Aug 7, 2008.
The use of ZnO in transparent type MIS solar cells
P. Petrou, R. Singh, and D. E. Brodie
The efficiency of transparent type MIS solar cells is often below the theoretical estimate due to the simultaneous requirement that the thin metal film have good transparency and high conductivity. In this letter we report the properties of ZnO on Ti as a combined transparent conducting (TC) layer w ... [Appl. Phys. Lett. 35, 930 (2008)] published Thu Aug 7, 2008.
Weak field magnetoresistance skewness imposed by magnetic field
D. S. Kyriakos and N. A. Economou
The effect of a magnetic field on any crystalline material is to introduce an anisotropy in the electric resistivity. This letter examines the anisotropy which appears in the (001) plane of cubic crystals. Compact formulas are developed which show that in general the extreme values of the resistivit ... [Appl. Phys. Lett. 35, 894 (2008)] published Thu Aug 7, 2008.
Calculated and measured efficiencies of thin-film shallow-homojunction GaAs solar cells on Ge substrates
John C. C. Fan, Carl O. Bozler, and Barbara J. Palm
By using a simple analytical model for GaAs solar cells with the nu+/p/p shallow-homojunction structure, we have obtained good between compter calculations and experimental data for the external quantum efficiency and AM1 conversion efficiency of thin-film GaAs cells with different values of layer ... [Appl. Phys. Lett. 35, 875 (2008)] published Thu Aug 7, 2008.
Small changes in work function of the TiC(001) surface with chemisorption of O[sub 2] and H[sub 2]O
C. Oshima, T. Tanaka, M. Aono, R. Nishitani, S. Kawai et al.
Changes in work function of the TiC (001) surface have been measured against O and HO exposure by using photoelectron spectroscopy. The sticking rates are about 1/100 of those for elemental Ti-metal substrate. In the case of oxygen exposure, the work function increases monotonically from 3.8 to 4.2 ... [Appl. Phys. Lett. 35, 822 (2008)] published Thu Aug 7, 2008.
Ion-electron (configurational) interface states in MOS structures
E. Kamieniecki
A new model of the semiconductor-insulator interface states is proposed. Transitions between free and bound states of a system consisting of a charged center in the insulator and an electron in the semiconductor are considered in the model. By assuming that the charged centers are located at differe ... [Appl. Phys. Lett. 35, 807 (2008)] published Thu Aug 7, 2008.
Steady-state electron and hole space charge distribution in LPCVD silicon nitride films
F. L. Hampton and J. R. Cricchi
Trapped electron and hole space charge distributions in silicon nitride are derived from steady-state measurements of the change in flatband voltage versus the maximum field in the nitride. These measurements coupled with the Arnett-Yun model provide a good relative measure of the hole and electron ... [Appl. Phys. Lett. 35, 802 (2008)] published Thu Aug 7, 2008.
Composition measurements related to the Cu[sub 2]S/Zn[sub x]Cd[sub 1 - x]S heterojunction
L. C. Burton
Composition of zinc and cadmium have been measured for three key regions related to the formation of CuS on ZnCdX by aqueous ion exchange. These are the ion-exchange solution, the resulting CuS, and the ZnCdS near the CuS-ZnCd interface. It is found that the participation of zinc in the ion-exchange ... [Appl. Phys. Lett. 35, 780 (2008)] published Thu Aug 7, 2008.
The temperature dependence of band-to-band Auger recombination in silicon
L. Huldt, N. G. Nilsson, and K. G. Svantesson
The Auger recombination coefficient has been determined from the decay kinetics of highly excited silicon. It was found to be proportional to T, increasing from 3.0 x 10 to 4.6 x 10 cms in the temperature interval 195372 K. ... [Appl. Phys. Lett. 35, 776 (2008)] published Thu Aug 7, 2008.
Molybdenum trioxide (MoO[sub 3])/silicon photodiodes
C. Osterwald, G. Cheek, J. B. DuBow, and V. R. Pai Verneker
Molybdenum trioxide (MoO) has been deposited onto single-crystal p-type silicon by neutralized ion-beam sputter techniques. The results indicate that the diode behavior is a function of oxygen partial pressure during the reactive sputtering. Film thickness, deposition rate, index of refraction, resi ... [Appl. Phys. Lett. 35, 775 (2008)] published Thu Aug 7, 2008.
Cyclotron resonance in n-type In[sub 1 - x]Ga[sub x]As[sub y]P[sub 1 - y]
H. Brendecke, H. L. Stormer, and R. J. Nelson
First experimental data are presented on the nonparabolicity of the conduction band of InGaAsP lattice matched to InP. The values for the effective mass, determined from our energy-dependent measurements, are smaller than all previously reported values. The nonparabolicity of the conduction band is ... [Appl. Phys. Lett. 35, 772 (2008)] published Thu Aug 7, 2008.
Grain boundary states and varistor behavior in silicon bicrystals
C. H. Seager and G. E. Pike
The energy density of states in a Si grain boundary has been quantitatively determined for the first time. Since the deconvolution scheme used in this determination is a technique previously unapplied to real materials, the applicability of the model and the validity of the results were experimental ... [Appl. Phys. Lett. 35, 709 (2008)] published Thu Aug 7, 2008.
Polycrystalline silicon by glow discharge technique
F. Morin and M. Morel
Polycrystalline silicon was obtained by glow discharge decomposition of silane on heated amorphous substrates. The influence of substrate temperature on crystalline structure and electrical conductivity of silicon films was investigated. Textured polycrystalline films were obtained above 450 degree ... [Appl. Phys. Lett. 35, 686 (2008)] published Thu Aug 7, 2008.
Carrier recombination through donors/acceptors in heavily doped silicon
Chenming Hu and William G. Oldham
Carrier recombination in heavily doped semiconductors via shallow donor or acceptor states is analyzed. The results are in general agreement with experimental lifetime observations including the 1/n or 1/P dependence, and the insensitivity to temperature and to the dopant used. Capture cross section ... [Appl. Phys. Lett. 35, 636 (2008)] published Thu Aug 7, 2008.
Hall effect in reactively sputtered Cu[sub 2]S
John Y. Leong and Jick H. Yee
The Hall effect in thin films of reactively sputtered CuS was measured at temperatures from 90 to 300 degrees K. The hole concentration ranged from 10 to 2 x 10 cm. The hole mobility ranged from 5.5 to 9 cm/V s. The predominant scattering mechanisms are ionized impurity scattering at T<100 degrees ... [Appl. Phys. Lett. 35, 601 (2008)] published Thu Aug 7, 2008.
Optically controllable millimeter wave phase shifter
A. P. DeFonzo, Chi H. Lee, and P. S. Mak
We have demonstrated a new approach to controlling millimeter wave propagation with light. Phase shifts as high as 300 degrees /cm of 94-GHz millimeter waves were observed accompanied by less than 1 dB insertion loss. A straightforward model was found to account in detail for the observed behavior. ... [Appl. Phys. Lett. 35, 575 (2008)] published Thu Aug 7, 2008.
Cadmium-tin oxide films deposited by rf sputtering from a CdO-SnO[sub 2] target
N. Miyata, K. Miyake, T. Fukushima, and K. Koga
Cadmium-tin oxide (CTO) films with high conductivity and high transparency were prepared by rf sputtering from a CdO-SnO target in an Ar or Ar-O atmosphere. The resistivity of CTO films was 6.5 x 10 Omega in the film thickness range of 250015000 A, and the average transmission was 90% over the visi ... [Appl. Phys. Lett. 35, 542 (2008)] published Thu Aug 7, 2008.
Highly doped evaporated amorphous silicon by alkali implantation
W. Beyer, A. Barna, and H. Wagner
Evaporated films of amorphous silicon can be doped interstitially by implantation of alkali ions. Room temperature conductivity values as high as sigma=2 x 10 (Omega cm) and activation energies of sigma as low as 0.25 eV are obtained by implantation of 1% potassium in films prepared with a low rate ... [Appl. Phys. Lett. 35, 539 (2008)] published Thu Aug 7, 2008.
Direct injection readout of the p-n PbS-Si heterojunction detector
A. J. Steckl, K. Y. Tam, and M. E. Motamedi
An n-channel MOSFET circuit implemented within a CMOS structure has been used to test the feasibility of integrating the infrared signal readout within a PbS-Si heterojunction detector (HJD) array. The efficiency of the source-coupled direct injection readout was determined from eta=I[prime]/I, wher ... [Appl. Phys. Lett. 35, 537 (2008)] published Thu Aug 7, 2008.
The quantum yield of silicon in the visible
Jon Geist and Edward F. Zalewski
Extremely high accuracy measurements of the internal quantum efficiency of shallow-junction silicon photodetectors were fit with various theoretical models. The internal quantum efficiency was found to be rather model independent indicating its possible use as a radiometric standard. The results of ... [Appl. Phys. Lett. 35, 503 (2008)] published Thu Aug 7, 2008.
Antireflection properties of indium tin oxide (ITO) on silicon for photovoltaic applications
G. Cheek, A. Genis, J. B. DuBow, and V. R. Pai Verneker
The short-circuit current density (J) of indium tin oxide (ITO/silicon solar cells has been shown both theoretically and experimentally to be a function of the thickness of the ion beam sputtered ITO layer. These results can be accounted for by computing the optical reflection from the ITO/silicon i ... [Appl. Phys. Lett. 35, 495 (2008)] published Thu Aug 7, 2008.
Impurity and phonon scattering in layered structures
K. Hess
The scattering rates for the electron-impurity and the electron-phonon interactions in semiconductor multilayer heterojunction structures are calculated. It is found that phonon scattering is enhanced in such structures, whereas, impurity scattering can be strongly reduced at low temperatures as fou ... [Appl. Phys. Lett. 35, 484 (2008)] published Thu Aug 7, 2008.
Negative differential resistance through real-space electron transfer
K. Hess, H. Morkoc, H. Shichijo, and B. G. Streetman
A new mechanism is proposed to obtain negative differential resistance in layered heterostructures for conduction parallel to the interface. The mechanism is based on hot-electron thermionic emission from high-mobility GaAs into low-mobility AlGaAs. Preliminary calculations indicate that high peak-t ... [Appl. Phys. Lett. 35, 469 (2008)] published Thu Aug 7, 2008.
Current conduction in Cr-MIS solar cells on single-crystal p-silicon
K. Rajkanan and W. A. Anderson
New information has been obtained about the current conduction in Cr-MIS solar cells by studying their current-voltage relationship over a wide range of temperatures. It is demonstrated that majority-carrier tunneling over the combined barrier due to the interfacial oxide and the space-charge region ... [Appl. Phys. Lett. 35, 421 (2008)] published Thu Aug 7, 2008.
Extension of a theorem used in the investigation of p-n junctions with the scanning electron microscope to arbitrary geometries and arbitrarily inhomogeneous material
Oldwig von Roos
It is shown that the relationship lim [partial-derivative]I/ [partial-derivative]n= (s/D) I connecting the normal derivative of the short circuit I generated by an electron or ion beam in a P-N junction with the surface recombination velocity s and the diffusion constant D is valid for arbitrary jun ... [Appl. Phys. Lett. 35, 408 (2008)] published Thu Aug 7, 2008.
Photothermal effect at TiO[sub 2] electrodes in a photoelectrochemical cell
Franco Decker, J. F. Juliao, and M. Abramovich
Anomalous photoresponse of n-TiO in a photoelectrochemical cell was previously observed to be induced by light of energy lower than the bandgap. This photoresponse was attributed to surface states at the TiO-electrolyte interface. We studied this effect at stationary and rotating disk TiO electrodes ... [Appl. Phys. Lett. 35, 397 (2008)] published Thu Aug 7, 2008.
Photoconductive imaging using hydrogenated amorphous silicon film
Y. Imamura, S. Ataka, Y. Takasaki, C. Kusano, T. Hirai et al.
Highly resistive hydrogenated amorphous-silicon film has been fabricated and examined as blocking-type photoconductive target of a vidicon-type image pickup tube. The results indicate that this novel silicon vidicon has many advantages over conventional ones. ... [Appl. Phys. Lett. 35, 349 (2008)] published Thu Aug 7, 2008.
Anomalous electrical and optical characteristics of GaAs/Al[sub x]Ga[sub 1 - x]As heterostructure materials
B. Wakefield, J. L. Stevenson, R. M. Redstall, and T. Ambridge
GaAs/AlGaAs double-heterostructure layers grown by conventional LPE have been examined by three separate electrical and optical techniques. Some material has exhibited characteristics not previously detected in epilayers grown singly. Our central observation is that Ge-doped passive and active layer ... [Appl. Phys. Lett. 35, 347 (2008)] published Thu Aug 7, 2008.
Optical derivative measurements of the electrical parameters for a junction diode
Thomas L. Paoli
A derivative technique is presented to determine optically the electrical parameters of a p-n junction. The method relies upon the saturation produced in the optically generated current delivered to a load resistor as a result of increases in either the average optical power incident on the p-n junc ... [Appl. Phys. Lett. 35, 339 (2008)] published Thu Aug 7, 2008.
Nonalloyed Ohmic contacts to n-GaAs by pulse-electron-beam-annealed selenium implants
R. L. Mozzi, W. Fabian, and F. J. Piekarski
Nonalloyed Ohmic contacts to n-GaAs have been formed by vapor deposition of TiPtAu on pulse-electron-beam-annealed Se-implanted surfaces. Peak carrier concentrations were about 1.2 x 10/cm, yielding a specific contact resistance r<~6 x 10 Omega cm. ... [Appl. Phys. Lett. 35, 337 (2008)] published Thu Aug 7, 2008.
On the thermoelectric amplification of sound in semiconductors
M. A. Tenan, A. Marotta, and L. C. M. Miranda
The possibility of sound amplification in a semiconductor subjected to an external temperature gradient is discussed. It is shown that for kl<<1 and short-circuited samples, the temperature gradient threshold for amplification varies inversely proportional to (kl). ... [Appl. Phys. Lett. 35, 321 (2008)] published Thu Aug 7, 2008.
Transformation from Ohmic to offset behavior for the on state of an amorphous semiconductor threshold switch for interruptions greater than 12 ns
Gary C. Vezzoli
In measuring the on-state I-V curve of an amorphous semiconductor threshold switch it is essential that the addressing voltage pulse does not allow a subholding voltage interval which is longer than a ''distribution free carrier lifetime'' in order that only on-state properties be detected. If the v ... [Appl. Phys. Lett. 35, 288 (2008)] published Thu Aug 7, 2008.
Observation of two-dimensional electrons in LPE-grown GaAs-Al[sub x]Ga[sub 1 - x]As heterojunctions
D. C. Tsui and R. A. Logan
We have observed a two-dimensional electron gas at the interface of asymmetrically doped GaAs-AlGaAs heterojunctions grown by LPE. Our results demonstrate unequivocally that LPE can be used to grow GaAs-AlGaAs heterojunctions with interfacial electrical properties comparable to those achieved by MBE ... [Appl. Phys. Lett. 35, 99 (2008)] published Thu Aug 7, 2008.
Molecular beam epitaxial growth of low-resistivity ZnSe films
Takafumi Yao, Yunosuke Makita, and Shigeru Maekawa
Single-crystalline films of low-resistivity ZnSe have been successfully grown by molecular beam epitaxy (MBE). The film shows good crystallinity, having a smooth and flat surface as revealed by RHEED and SEM investigations. The resistivity of as-grown MBE ZnSe is low (typically ~1 Omega cm) and the ... [Appl. Phys. Lett. 35, 97 (2008)] published Thu Aug 7, 2008.
Measurements of the rectifying barrier heights of the various iridium silicides with n-Si
J. de Sousa Pires, P. Ali, B. Crowder, F. d'Heurle, S. Petersson et al.
The barrier height of Schottky diodes formed with and n-type silicon substrates and Ir, IrSi, IrSi, and IrSi have been determined by means of photoresponse, capacitance, and forward I/V measurements. In all cases the barrier height values are quite high, in excess of 0.85 eV. For Ir, IrSi, and IrS ... [Appl. Phys. Lett. 35, 202 (2008)] published Thu Aug 7, 2008.
Electron energy loss spectroscopy studies of the Si-SiO[sub 2] interface
T. Adachi and C. R. Helms
We have performed, for the first time, measurements of the electronic structure of the Si-SiO interface with electron energy loss spectroscopy (ELS) in connection with argon-ion sputtering. We have measured the depth profiles of both the 5.1- and 7.2-eV ELS peaks, which have been previously observed ... [Appl. Phys. Lett. 35, 199 (2008)] published Thu Aug 7, 2008.
Shallow acceptors and p-type ZnSe
K. Kosai, B. J. Fitzpatrick, H. G. Grimmeiss, R. N. Bhargava, and G. F. Neumark
Shallow acceptors have been incorporated in ZnSe by liquid-phase epitaxy using Bi as a solvent. Epilayers with Li, Na, N, and P as dopants were proven to be p type by establishing the position of the Fermi level by photocapacitance and photoconductivity measurements, and by measuring the potential d ... [Appl. Phys. Lett. 35, 194 (2008)] published Thu Aug 7, 2008.
Improved electrical mobilities from implanting InP at elevated temperatures
D. Eirug Davies, J. J. Comer, J. P. Lorenzo, and T. G. Ryan
InP has been implanted with silicon to investigate the effect of implantation temperature on the postannealed electrical mobility. A significant improvement, by a factor of ~2, occurs on implanting at 200 degrees C rather than at room temperature. Dislocations found after the room-temperature but n ... [Appl. Phys. Lett. 35, 192 (2008)] published Thu Aug 7, 2008.
Current-field characteristics of oxides grown from polycrystalline silicon
Chenming Hu, Ying Shum, Tom Klein, and Elroy Lucero
A new technique determined the J-E characteristics of silicon dioxide grown from polycrystalline silicon with greatly improved sensitivity. More importantly, the current density was measured over a 10-decade range without the problem of current drift or uncertainty about the field at the cathode sur ... [Appl. Phys. Lett. 35, 189 (2008)] published Thu Aug 7, 2008.
Revised model of asymmetric p-n junctions
David Redfield
The standard physical model by which p-n junctions in semiconductors are generally analyzed is shown to need significant revisions when applied to strongly asymmetrical junctions, such as commonly used in diffused silicon transistor emitters and solar cells. The potential, field, and space-charge de ... [Appl. Phys. Lett. 35, 182 (2008)] published Thu Aug 7, 2008.
Thin film MOSFET's fabricated in laser-annealed polycrystalline silicon
K. F. Lee, J. F. Gibbons, K. C. Saraswat, and T. I. Kamins
Both depletion- and enhancement-mode MOSFET's have been fabricated with the active transistor channels in laser-annealed polycrystalline-silicon films. A dose of 3 x 10 P/cm was implanted at 100 keV into 0.5-[mu]m-thick poly-silicon films for the depletion-mode device, and a dose of 3 x 10 B/cm was ... [Appl. Phys. Lett. 35, 173 (2008)] published Thu Aug 7, 2008.
Minority-carrier diffusion coefficients in highly doped silicon
J. Dziewior and D. Silber
Direct experimental determination of minority-carrier mobilities and corresponding diffusion coefficients in highly doped p- and n-type silicon have apparently not been performed until now. We have determined the minority-carrier diffusion coefficient in phosphorus- and boron-doped silicon (doping r ... [Appl. Phys. Lett. 35, 170 (2008)] published Thu Aug 7, 2008.
Threshold energies for impact ionization by electrons and holes in InP
T. P. Pearsall
The threshold conditions for impact ionization in InP at 300 K have been calculated from the electronic band structure along the three major symmetry axes. These calculations show that conditions for electron-initiated impact ionization in InP are much more favorable than in GaAs. ... [Appl. Phys. Lett. 35, 168 (2008)] published Thu Aug 7, 2008.
Four-wave interactions in acoustoelectric integrating correlators
R. W. Ralston and E. Stern
Four-wave acoustoelectric interactions have been observed in an integrating correlator which provide both significantly improved device performance over that achieved with three-wave interactions and make possible a unique signal-processing function: triple-product correlation. These interactions in ... [Appl. Phys. Lett. 35, 150 (2008)] published Thu Aug 7, 2008.
Annihilation of frozen-in point defects in GaP by thermal and recombination-induced processes
C. Werkhoven, J. H. T. Hengst, and C. van Opdorp
Minority-carrier-lifetime measurements on heat-treated rapidly cooled LEC-grown GaP reveal strong nonradiative recombination at frozen-in point defects. Cathodoluminescence line scan studies show that during slow cooling the point defects introduced during heating are removed by diffusion to disloca ... [Appl. Phys. Lett. 35, 136 (2008)] published Thu Aug 7, 2008.
Very-low-noise silicon avalanche photodiodes made by the channeling of aluminum in silicon
E. T. J. M. Smeets and J. Politiek
A silicon nppip reach-through avalanche photodiode is described, where the p region is made by the channeling of aluminum atoms in silicon. Effective noise factors of about 0.01 have been realized. The influence of the channeling on device parameters is discussed. ... [Appl. Phys. Lett. 35, 112 (2008)] published Thu Aug 7, 2008.
Minority-carrier generation in n-InP/SiO[sub 2] capacitors
J. Stannard and R. L. Henry
Zerbst and DLTS measurements have been used to study the processes active for minority-carrier generation in n-InP/SiO capacitors. Surface generation velocities near 10 cm/sec were observed, and generation in the bulk proceeds via a level below midgap which has a large cross section for electron emi ... [Appl. Phys. Lett. 35, 86 (2008)] published Thu Aug 7, 2008.
Junction formation with pure and doped polyacetylene
M. Ozaki, D. L. Peebles, B. R. Weinberger, C. K. Chiang, S. C. Gau et al.
A variety of rectifying junctions have been fabricated using doped and undoped (CH). Schottky diodes formed between metallic AsF-doped (CH) and n-type semiconductors indicate high [CH(AsF)] electronegativity. The p-type character of undoped trans- (CH) is confirmed by Schottky-barrier formation with ... [Appl. Phys. Lett. 35, 83 (2008)] published Thu Aug 7, 2008.
Stress in thermal SiO[sub 2] during growth
E. P. EerNisse
Stress present in thermal SiO at temperatures during growth in wet O has been measured as a function of growth temperature. During growth at 950 degrees C and below, compressive stress on the order of 7 x 10 dyn/cm is generated in the SiO. During growth at 975 and 1000 degrees C, the SiO grows in ... [Appl. Phys. Lett. 35, 8 (2008)] published Thu Aug 7, 2008.
Background carrier concentration and electron mobility in LPE In[sub 1 - x]Ga[sub x]As[sub y]P[sub 1 - y] layers
P. D. Greene, S. A. Wheeler, A. R. Adams, A. N. El-Sabbahy, and C. N. Ahmad
Lattice-matched and nominally undoped layers of InGaAsP were grown by liquid-phase epitaxy on semi-insulating (100) InP substrates. The background carrier concentration for a range of compositions was about 2 x 10 cm when unbaked melts were used, but with prebaking 2.8 x 10 cm was achieved. The elec ... [Appl. Phys. Lett. 35, 78 (2008)] published Thu Aug 7, 2008.
Resistivity measurement of thin semiconductor films on metallic substrates
Steve Hogan, Sigurd Wagner, and Frank S. Barnes
The resistivity of thin polycrystalline films of cadmium deposited on brass substrates has been measured by a microwave technique. The samples, of the type employed in solar-cell research, form the plane reflector of a semiconfocal Fabry-Perot millimeter-wave interferometer. The resistivity is deriv ... [Appl. Phys. Lett. 35, 77 (2008)] published Thu Aug 7, 2008.
Photovoltaic effect in Cu/CuGaSe[sub 2] Schottky barriers
J. Stankiewicz and W. Giriat
Cu/CuGaSe Schottky barriers have been prepared by vacuum deposition of copper on p-type CuGaSe single crystals with a resistivity of 10 Omega cm. The photovoltaic properties of such cells have been investigated. Under the AM1 condition these cells exhibit a solar-energy conversion efficiency of 3.5% ... [Appl. Phys. Lett. 35, 70 (2008)] published Thu Aug 7, 2008.
A majority-carrier camel diode
J. M. Shannon
A majority-carrier diode concept is described in which current flow is controlled by a potential hump in the bulk of a semiconductor. Devices of this type, called camel diodes, having ideality factors <2 have been realized using low-energy ion implantation. ... [Appl. Phys. Lett. 35, 63 (2008)] published Thu Aug 7, 2008.
Preparation and properties of CuInS[sub 2] thin films produced by exposing sputtered Cu-In films to an H[sub 2]S atmosphere
Steven P. Grindle, Charles W. Smith, and Steven D. Mittleman
CuInS thin films have been made from copper, indium, and hydrogen sulfide gas using a two-step technique which involves exposing Cu-In films produced by sputtering pure copper and pure indium to HS gas diluted with argon. X-ray diffraction, Auger electron spectroscopy, optical transmission, and elec ... [Appl. Phys. Lett. 35, 24 (2008)] published Thu Aug 7, 2008.
Resistivity changes in laser-annealed polycrystalline silicon during thermal annealing
Tadashi Shibata, Hisakazu Iizuka, Susumu Kohyama, and J. F. Gibbons
Polycrystalline silicon layers heavily doped with phosphorus or arsenic were irradiated with a Nd : YAG pulsed laser beam. A 4050% reduction in sheet resistivity was obtained by laser annealing. However, during subsequent heat treatments the resistivity increased to a value which was higher than the ... [Appl. Phys. Lett. 35, 21 (2008)] published Thu Aug 7, 2008.
Steady-State Currents through Nanodevices: A Scattering-States Numerical Renormalization-Group Approach to Open Quantum Systems
Frithjof B. Anders
We propose a numerical renormalization group (NRG) approach to steady-state currents through nanodevices. A discretization of the scattering-states continuum ensures the correct boundary condition for an open quantum system. We introduce two degenerate Wilson chains for current carrying left- and ri ... [Phys. Rev. Lett. 101, 066804 (2008)] published Thu Aug 7, 2008.
Evolution of the Fermi Surface across a Magnetic Order-Disorder Transition in the Two-Dimensional Kondo Lattice Model: A Dynamical Cluster Approach
L. C. Martin and F. F. Assaad
We use the dynamical cluster approximation, with a quantum Monte Carlo cluster solver on clusters of up to 16 orbitals, to investigate the evolution of the Fermi surface across the magnetic order-disorder transition in the two-dimensional doped Kondo lattice model. In the paramagnetic phase, we obse ... [Phys. Rev. Lett. 101, 066404 (2008)] published Thu Aug 7, 2008.
Effective tuning of the charge state of a single InAs/GaAs quantum dot by an external magnetic field
E. S. Moskalenko, L. A. Larsson, M. Larsson, P. O. Holtz, W. V. Schoenfeld et al.
A microphotoluminescence study of single InAs/GaAs quantum dots (QDs) in the presence of an applied external magnetic field is presented. Attention is focused on the redistribution between the spectral lines of a single QD observed at increasing magnetic field parallel to the growth direction (Farad ... [Phys. Rev. B 78, 075306 (2008)] published Wed Aug 6, 2008.
Orientation-dependent conductance study of pentacene nanocrystals by conductive atomic force microscopy
Wei-Shan Hu, Yu-Tai Tao, Yen-Fu Chen, and Chia-Seng Chang
Oriented pentacene nanocrystals with long molecular axis either parallel or perpendicular to a Au substrate were prepared on a bare Au surface or a self-assembled monolayer (SAM)-modified Au surface, respectively. The conductance across the differently oriented pentacene crystals were measured by co ... [Appl. Phys. Lett. 93, 053304 (2008)] published Wed Aug 6, 2008.
Hall effect on the triangular lattice
G. Leon, C. Berthod, T. Giamarchi, and A. J. Millis
We investigate the high-frequency Hall effect on a two-dimensional triangular lattice with nearest-neighbor hopping and a local Hubbard interaction. The complete temperature and doping dependencies of the high-frequency Hall coefficient R are evaluated analytically and numerically for small, interme ... [Phys. Rev. B 78, 085105 (2008)] published Wed Aug 6, 2008.
Orientation-dependent conductance study of pentacene nanocrystals by conductive atomic force microscopy
Wei-Shan Hu, Yu-Tai Tao, Yen-Fu Chen, and Chia-Seng Chang
Oriented pentacene nanocrystals with long molecular axis either parallel or perpendicular to a Au substrate were prepared on a bare Au surface or a self-assembled monolayer (SAM)-modified Au surface, respectively. The conductance across the differently oriented pentacene crystals were measured by co ... [Appl. Phys. Lett. 93, 053304 (2008)] published Wed Aug 6, 2008.
Effects of hydrogen anneals on oxygen deficient SrTiO[sub 3 - x] single crystals
Bharat Jalan, Roman Engel-Herbert, Thomas E. Mates, and Susanne Stemmer
The influence of hydrogen gas anneals on the electrical properties of nominally undoped, oxygen-deficient SrTiO single crystals was investigated. Titanium getter layers and vacuum anneals were used to obtain oxygen-deficient SrTiO with a low electrical resistivity. These crystals showed an optical a ... [Appl. Phys. Lett. 93, 052907 (2008)] published Wed Aug 6, 2008.
Effect of ruthenium oxide electrode on the resistive switching of Nb-doped strontium titanate
Musarrat Hasan, Rui Dong, H. J. Choi, D. S. Lee, D.-J. Seong et al.
We studied resistance switching characteristics of ruthenium oxide (RuO)/niobium-doped strontium titanate (Nb:STO) contact. With increasing oxygen content of oxide electrode, the resistance window was improved. The switching speed of RuO electrode also showed improvement compared to platinum (Pt) el ... [Appl. Phys. Lett. 93, 052908 (2008)] published Wed Aug 6, 2008.
Nonlinear characteristics of T-branch junctions: Transition from ballistic to diffusive regime
H. Irie, Q. Diduck, M. Margala, Roman Sobolewski, and M. J. Feldman
Nonlinear electrical characteristics of nanostructured T-branch junctions (TBJs) made of two-dimensional electron gas in an InGaAs/InAlAs heterostructure were studied by a systematic variation of both the device size and the operating temperature. We have found that two distinct mechanisms are respo ... [Appl. Phys. Lett. 93, 053502 (2008)] published Wed Aug 6, 2008.
Nearly intrinsic exciton lifetimes in single twin-free GaAs/AlGaAs core-shell nanowire heterostructures
S. Perera, M. A. Fickenscher, H. E. Jackson, L. M. Smith, J. M. Yarrison-Rice et al.
CW and time-resolved photoluminescence measurements are used to investigate exciton recombination dynamics in GaAs/AlGaAs heterostructure nanowires grown with a recently developed technique which minimizes twinning. A thin capping layer is deposited to eliminate the possibility of oxidation of the A ... [Appl. Phys. Lett. 93, 053110 (2008)] published Wed Aug 6, 2008.
Deep level transient spectroscopy for diodes with large leakage currents
D. S. Day, M. J. Helix, K. Hess, and B. G. Streetman
A Deep Level Transient Spectroscopy (DLTS) system is described for measuring deep levels in diodes exhibiting large leakage currents. A capacitance bridge employing the diode to be tested along with a dummy diode of similar characteristics is used. The DLTS spectrum of a leaky GaAs planar diode is m ... [Rev. Sci. Instrum. 50, 1571 (2008)] published Wed Aug 6, 2008.
Measurement of magnetostriction coefficients of epitaxial garnet films
G. P. Vella-Coleiro
A technique for measuring the magnetostriction coefficients of epitaxial garnet films on 50-mm-diam wafers is described. The measurement is based on the shift of the microwave ferrimagnetic resonance produced by stressing the film, which is achieved by supporting the wafer around its circumference a ... [Rev. Sci. Instrum. 50, 1130 (2008)] published Wed Aug 6, 2008.
Precise diode method for recording contact potential changes caused by gas adsorption
K. Christmann and H. Herz
A low-temperature recording diode is described which allows the determination of adsorption-induced contact potential differences with an accuracy of better than 0.5 mV. Some experimental work function results of the hydrogen adsorption on platinum (111) and (997) single-crystal faces are presented ... [Rev. Sci. Instrum. 50, 988 (2008)] published Wed Aug 6, 2008.
Resonant torsional apparatus for contactless measurements of electrical conductivity and magnetic susceptibility of solids
J. R. Hendrickson and John Philbrook
We have constructed a torsional resonance apparatus for contact-free measurements of the electrical conductivity of solids. Owing to its use of modulation spectroscopy, the technique achieves considerable enhancement of sensitivity compared to previous contactless methods. Conductivities in the rang ... [Rev. Sci. Instrum. 50, 849 (2008)] published Wed Aug 6, 2008.
Simple apparatus for the discrimination of the majority carrier type in semiconductors
H. G. Brion and R. Schettler
An apparatus is proposed, showing the majority carrier type in semiconductors via an optical display. The operating method is based on the change in sign of the thermoelectric power. ... [Rev. Sci. Instrum. 50, 131 (2008)] published Wed Aug 6, 2008.
The determination of the metal-dielectric interface barrier height from the open-circuit isothermal charging current
E. R. Neagu, R. M. Neagu, C. J. Dias, M. Carmo Lanca, and J. N. Marat-Mendes
There is a sustained interest both from theoretical and from practical points of view to understand the isothermal charging and the isothermal discharging currents in dielectrics. The measured currents are analyzed either in terms of polarization mechanisms or in terms of charge injection/extraction ... [J. Appl. Phys. 104, 034102 (2008)] published Wed Aug 6, 2008.
An experimental study on the molecular organization and exciton diffusion in a bilayer of a porphyrin and poly(3-hexylthiophene)
Annemarie Huijser, Tom J. Savenije, Avi Shalav, and Laurens D. A. Siebbeles
The exciton root-mean-square displacement (Lambda) in regioregular poly(3-hexylthiophene) (P3HT) deposited onto meso-tetrakis (n-methyl-4-pyridyl) porphyrin tetrachloride (HTMPyP) has been determined from the photovoltaic response of a device based on these materials in a bilayer configuration. Exci ... [J. Appl. Phys. 104, 034505 (2008)] published Wed Aug 6, 2008.
Bridge Between Abelian and Non-Abelian Fractional Quantum Hall States
N. Regnault, M. O. Goerbig, and Th. Jolicoeur
We propose a scheme to construct the most prominent Abelian and non-Abelian fractional quantum Hall states from K-component Halperin wave functions. In order to account for a one-component quantum Hall system, these SU(K) colors are distributed over all particles by an appropriate symmetrization. Nu ... [Phys. Rev. Lett. 101, 066803 (2008)] published Wed Aug 6, 2008.
Phase Diagram of Na[sub x]CoO[sub 2] Studied By Gutzwiller Density-Functional Theory
Guang-Tao Wang, Xi Dai, and Zhong Fang
The ground state of NaCoO (0.0
Kondo Proximity Effect: How Does a Metal Penetrate into a Mott Insulator?
R. W. Helmes, T. A. Costi, and A. Rosch
We consider a heterostructure of a metal and a paramagnetic Mott insulator using an adaptation of dynamical mean-field theory to describe inhomogeneous systems. The metal can penetrate into the insulator via the Kondo effect. We investigate the scaling properties of the metal-insulator interface clo ... [Phys. Rev. Lett. 101, 066802 (2008)] published Wed Aug 6, 2008.
Terahertz conductivity of thin metal films
N. Laman and D. Grischkowsky
The conductivities of thin Al, Au, and Ag films were measured via their transmission at terahertz frequencies. The conductivities of all the films, particularly the thinner films and Al films, were much smaller than their bulk dc values. This reduced conductivity can be quantitatively understood in ... [Appl. Phys. Lett. 93, 051105 (2008)] published Tue Aug 5, 2008.
Carrier relaxation through two-electron process during photoconduction in highly UV sensitive quasi-one-dimensional ZnO nanowires
A. Bera and D. Basak
We have investigated the carrier relaxation process during photoconduction in quasi-one-dimensional (Q1D) ZnO nanowires (NWs) of diameters 2936 nm on different substrates using photocurrent transient measurements. Ultraviolet (UV) sensitive NWs show around three to four orders of change in the phot ... [Appl. Phys. Lett. 93, 053102 (2008)] published Tue Aug 5, 2008.
Band gap engineering for La aluminate dielectrics on Si (100)
Hua Jin, Young Joon Cho, Suhk Kun Oh, Hee Jae Kang, Ju Chul Park et al.
La aluminate (LaO)(AlO) films were grown by atomic layer deposition method, for which the conduction band offset, valence band offset, and band gap were obtained by using x-ray photoelectron spectroscopy and reflection electron energy loss spectroscopy. The valence band offsets were nearly unchanged ... [Appl. Phys. Lett. 93, 052904 (2008)] published Tue Aug 5, 2008.
Phonon-assisted tunneling between singlet states in two-electron quantum dot molecules
A. Grodecka, P. Machnikowski, and J. Forstner
We study phonon-assisted electron tunneling in semiconductor quantum dot molecules. In particular, singlet-singlet relaxation in a two-electron-doped structure is considered. The influence of Coulomb interaction is discussed via comparison with a single-electron system. We find that the relaxation r ... [Phys. Rev. B 78, 085302 (2008)] published Tue Aug 5, 2008.
Efficient [script O](N[sup 2]) approach to solve the Bethe-Salpeter equation for excitonic bound states
F. Fuchs, C. Rodl, A. Schleife, and F. Bechstedt
Excitonic effects in optical spectra and electron-hole pair excitations are described by solutions of the Bethe-Salpeter equation (BSE) that accounts for the Coulomb interaction of excited electron-hole pairs. Although for the computation of excitonic optical spectra in an extended frequency range e ... [Phys. Rev. B 78, 085103 (2008)] published Tue Aug 5, 2008.
Evolution of the spectral weight in the Mott-Hubbard series SrVO[sub 3]-CaVO[sub 3]-LaVO[sub 3]-YVO[sub 3]
R. J. O. Mossanek, M. Abbate, T. Yoshida, A. Fujimori, Y. Yoshida et al.
We studied the Mott-Hubbard series SrVO-CaVO-LaVO-YVO with high-energy photoemission. The features in the experimental spectra were interpreted using cluster model calculations. The valence-band photoemission results show very interesting trends across the Mott-Hubbard series: (i) From SrVO to CaVO, ... [Phys. Rev. B 78, 075103 (2008)] published Tue Aug 5, 2008.
Resonant excitonic emission of a single quantum dot in the Rabi regime
R. Melet, V. Voliotis, A. Enderlin, D. Roditchev, X. L. Wang et al.
We report on coherent resonant emission of the fundamental exciton state in a single semiconductor GaAs quantum dot. A resonant regime with picosecond laser excitation is realized by embedding the quantum dots in a one-dimensional waveguiding structure. As the pulse intensity is increased, Rabi osci ... [Phys. Rev. B 78, 073301 (2008)] published Tue Aug 5, 2008.
Edge-channel interference controlled by Landau level filling
L. V. Litvin, A. Helzel, H.-P. Tranitz, W. Wegscheider, and C. Strunk
We study the visibility of Aharonov-Bohm interference in an electronic Mach-Zehnder interferometer in the integer quantum Hall regime. The visibility is controlled by the filling factor nu and is observed only between nu[approximate]2.0 and 1.0, with an unexpected maximum near nu=1.5. Three energy s ... [Phys. Rev. B 78, 075303 (2008)] published Tue Aug 5, 2008.
Fitting of local densities in periodic systems
Lorenzo Maschio and Denis Usvyat
We present a formalism for density fitting, a widely used method in molecular context, to approximate the electron repulsion integrals between local densities in periodic systems. An efficient treatment is achieved through a separation of the fitting into a reciprocal space part, done with an extend ... [Phys. Rev. B 78, 073102 (2008)] published Tue Aug 5, 2008.
Real-time, local basis-set implementation of time-dependent density functional theory for excited state dynamics simulations
Sheng Meng and Efthimios Kaxiras
We present a method suitable for large-scale accurate simulations of excited state dynamics within the framework of time-dependent density functional theory (DFT). This is achieved by employing a local atomic basis-set representation and real-time propagation of excited state wave functions. We impl ... [J. Chem. Phys. 129, 054110 (2008)] published Tue Aug 5, 2008.
Resonance energy transfer from a dye molecule to graphene
R. S. Swathi and K. L. Sebastian
We study the distance dependence of the rate of resonance energy transfer from the excited state of a dye to the pi system of graphene. Using the tight-binding model for the pi system and the Dirac cone approximation, we obtain the analytic expression for the rate of energy transfer from an electron ... [J. Chem. Phys. 129, 054703 (2008)] published Tue Aug 5, 2008.
Surface crystallography and electronic structure of potassium yttrium tungstate
V. V. Atuchin, L. D. Pokrovsky, O. Yu. Khyzhun, A. K. Sinelnichenko, and C. V. Ramana
Structural and electronic characteristics of KY(WO) (KYW) (010) crystal surfaces have been studied using reflection high-energy electron diffraction (RHEED) and x-ray photoelectron spectroscopy (XPS). The results indicate that the crystal structure and chemical composition of the mechanically polish ... [J. Appl. Phys. 104, 033518 (2008)] published Tue Aug 5, 2008.
Improved thermoelectric performance in polycrystalline p-type Bi[sub 2]Te[sub 3] via an alkali metal salt hydrothermal nanocoating treatment approach
Xiaohua Ji, Jian He, Zhe Su, Nick Gothard, and Terry M. Tritt
We report herein a proof-of-principle study of grain boundary engineering in the polycrystalline p-type BiTe system. Utilizing the recently developed hydrothermal nanocoating treatment technique, we fabricated an alkali-metal(s)-containing surface layer on the p-BiTe bulk grain, which in turn became ... [J. Appl. Phys. 104, 034907 (2008)] published Tue Aug 5, 2008.
Scattering potentials at Si-Ge and Sn-Ge impurity dimers on Ge(001) studied by scanning tunneling microscopy and ab initio calculations
Kota Tomatsu, Masamichi Yamada, Kan Nakatsuji, Fumio Komori, Binghai Yan et al.
Scattering potentials for pi electrons at Si-Ge and Sn-Ge dimers on a Ge(001) surface are studied by scanning tunneling microscopy and ab initio calculations. Phase-shift analysis of standing waves in dI/dV images reveals that Si and Sn atoms located in the conduction path of pi electrons form poten ... [Phys. Rev. B 78, 081401 (2008)] published Mon Aug 4, 2008.
Supercritical Coulomb impurities in gapped graphene
Vitor M. Pereira, Valeri N. Kotov, and A. H. Castro Neto
We study the problem of Coulomb field-induced charging of the ground state in a system of two-dimensional (2D) massive Dirac particlesgapped graphene. As in its 3D QED counterpart, the critical Coulomb coupling is renormalized to higher values compared to the massless case. We find that in gapped gr ... [Phys. Rev. B 78, 085101 (2008)] published Mon Aug 4, 2008.
Oscillatory Hall effect in high-mobility two-dimensional electron gases
Christoph Siegert, Arindam Ghosh, Michael Pepper, Ian Farrer, David A. Ritchie et al.
We report an unexpected anomaly in the zero-field Hall coefficient of two-dimensional electron systems in high-mobility GaAs/AlGaAs heterostructures. Our device layout allows the investigation of mesoscopic systems with variable Fermi energy as well as with tunable Hall probes. At very low temperatu ... [Phys. Rev. B 78, 081302 (2008)] published Mon Aug 4, 2008.
Linear conductance of an interacting carbon nanotube ring
Matthis Eroms, Leonhard Mayrhofer, and Milena Grifoni
Linear transport through a single-walled carbon nanotube ring, pierced by a magnetic field and capacitively coupled to a gate voltage source, is investigated starting from a model of interacting p electrons. Rings of armchair type are considered. The dc conductance, calculated in the limit of weak t ... [Phys. Rev. B 78, 075403 (2008)] published Mon Aug 4, 2008.
Spin-Orbit Hybridization Points in the Face-Centered-Cubic Cobalt Band Structure
M. Pickel, A. B. Schmidt, F. Giesen, J. Braun, J. Minar et al.
Linear magnetic dichroism is observed in spin-, time-, and energy-resolved two-photon photoemission from valence bands of epitaxial fcc cobalt on Cu(001). With image-potential states as spectator states we identify initial bulk and surface states with minority spin character as the source for dichro ... [Phys. Rev. Lett. 101, 066402 (2008)] published Mon Aug 4, 2008.
Nonadiabatic Charge Pumping in a Hybrid Single-Electron Transistor
Dmitri V. Averin and Jukka P. Pekola
We study theoretically current quantization in the charge turnstile based on the superconductornormal-metal single-electron transistor. The quantization accuracy is limited by either Andreev reflection or by Cooper-pairelectron cotunneling. The rates of these processes are calculated in the above-th ... [Phys. Rev. Lett. 101, 066801 (2008)] published Mon Aug 4, 2008.
Chirality-Induced Dynamic Kohn Anomalies in Graphene
Wang-Kong Tse, Ben Yu-Kuang Hu, and S. Das Sarma
We develop a theory for the renormalization of the phonon energy dispersion in graphene due to the combined effects of both Coulomb and electron-phonon (e-ph) interactions. We obtain the renormalized phonon energy spectrum by an exact analytic derivation of the phonon self-energy, finding three dist ... [Phys. Rev. Lett. 101, 066401 (2008)] published Mon Aug 4, 2008.
Understanding quantum interference in coherent molecular conduction
Gemma C. Solomon, David Q. Andrews, Thorsten Hansen, Randall H. Goldsmith, Michael R. Wasielewski et al.
Theory and experiment examining electron transfer through molecules bound to electrodes are increasingly focused on quantities that are conceptually far removed from current chemical understanding. This presents challenges both for the design of interesting molecules for these devices and for the in ... [J. Chem. Phys. 129, 054701 (2008)] published Fri Aug 1, 2008.
Intervalley splittings of Si quantum wells
S.-H. Park, Y. Y. Lee, and Doyeol Ahn
Intervalley splittings of Si quantum wells are studied using a multivalley effective mass theory and a finite element method. It is found that the contributions to the valley splitting mainly come from the quantum well interfaces and the external field. Especially the derivatives of the confinement ... [J. Appl. Phys. 104, 033703 (2008)] published Fri Aug 1, 2008.
Electrical, thermal, and elastic properties of the MAX-phase Ti[sub 2]SC
T. H. Scabarozi, S. Amini, P. Finkel, O. D. Leaffer, J. E. Spanier et al.
We report on the electronic, thermal, and elastic properties of the layered ternary, TiSC. Resistivity, Hall effect, and magnetoresistance were measured as a function of temperature between 2 and 300 K and at fields up to 9 T. The Hall coefficient is negative and roughly temperature independent. The ... [J. Appl. Phys. 104, 033502 (2008)] published Fri Aug 1, 2008.
Electrical transport properties of n-type (110)-oriented bismuth thin films grown at 110 K on glass substrates
Keng Shuo Wu and Ming Yau Chern
The structure and properties of the Bi thin films, grown by pulsed laser deposition at 110 K on glass substrates in vacuum, were found to be very different from those grown at higher temperatures. The preferred orientation of the films changed from (111), when grown at room temperature, to (110), as ... [J. Appl. Phys. 104, 033704 (2008)] published Fri Aug 1, 2008.
Numerical and experimental investigation of wedge tip radius effect on wedge plasmons
T. Ogawa, D. F. P. Pile, T. Okamoto, M. Haraguchi, M. Fukui et al.
We report numerical analysis and experimental observation of strongly localized plasmons guided by triangular metal wedges and pay special attention to the effect of smooth (nonzero radius) tips. Dispersion, dissipation, and field structure of such wedge plasmons are analyzed using the compact two-d ... [J. Appl. Phys. 104, 033102 (2008)] published Fri Aug 1, 2008.
Formation of metallic indium-tin phase from indium-tin-oxide nanoparticles under reducing conditions and its influence on the electrical properties
G. Guenther, G. Schierning, R. Theissmann, R. Kruk, R. Schmechel et al.
The correlation between defect structure, metal segregation, and electrical resistivity of indium-tin-oxide nanopowder upon treatment in reducing atmosphere was investigated. Morphology and defect structure have been investigated by in situ synchrotron x-ray diffraction and transmission electron mic ... [J. Appl. Phys. 104, 034501 (2008)] published Fri Aug 1, 2008.
The search for mechanically stable PbTe based thermoelectric materials
Yaniv Gelbstein, Zinovi Dashevsky, and Moshe P. Dariel
The search for alternative energy sources is nowadays at the forefront of applied research. In this context, thermoelectricity for direct energy conversion from thermal to electrical energy plays an important role, in particular, for the exploitation of waste heat [G. J. Snyder and E. S. Toberer, Na ... [J. Appl. Phys. 104, 033702 (2008)] published Fri Aug 1, 2008.
Investigation on copper phthalocyanine/multiwalled carbon nanotube interface
L. Lozzi, S. Santucci, F. Bussolotti, and S. La Rosa
The electronic and structural properties of copper phthalocyanine deposited onto multiwalled carbon nanotubes were studied as a function of the deposition thickness. The valence band and core level spectra were investigated using photoemission spectroscopy. A shift of the organic highest occupied mo ... [J. Appl. Phys. 104, 033701 (2008)] published Fri Aug 1, 2008.
Tight-binding calculations of ZnSe/Si wurtzite superlattices: Electronic structure and optical properties
A. Laref, W. Sekkal, S. Laref, and S. J. Luo
Our study is devoted to the theoretical investigation of the electronic and optical properties of (ZnSe)/(Si) (0001) wurtzite (WZ) superlattices (SLs) with the range n=m=118, giving special attention to the role of interface states at the ZnSi and SeSi polar interfaces. The calculations are performe ... [J. Appl. Phys. 104, 033103 (2008)] published Fri Aug 1, 2008.
Magnetoplasmons in layered graphene structures
Oleg L. Berman, Godfrey Gumbs, and Yurii E. Lozovik
We calculate the dispersion equations for magnetoplasmons in a single layer, a pair of parallel layers, a graphite bilayer, and a superlattice of graphene layers in a perpendicular magnetic field. We demonstrate the feasibility of a drift-induced instability of magnetoplasmons. The magnetoplasmon in ... [Phys. Rev. B 78, 085401 (2008)] published Fri Aug 1, 2008.
Validity of the Slater-Janak transition-state model within the LDA + U approach
Simone Sanna, Th. Frauenheim, and U. Gerstmann
Known with the name of the Slater-Janak transition-state model, Janak's theorem allows a calculation of charge transition levels by analyzing the Kohn-Sham eigenvalues of the density-functional theory without the need of explicitly comparing differently charged systems. Unfortunately, the usual loca ... [Phys. Rev. B 78, 085201 (2008)] published Fri Aug 1, 2008.
Multiterminal multimode spin-dependent scattering matrix formalism: Electron and hole quantum spin transport in multiterminal junctions
P. Brusheim, D. Csontos, U. Zulicke, and H. Q. Xu
We present a derivation of a scattering matrix method providing an exact multimode solution to spin-dependent quantum transport in multiterminal structures. The method is formulated in a general language such that it can readily be applied to any spin-S system with spin interactions. We apply the fo ... [Phys. Rev. B 78, 085301 (2008)] published Fri Aug 1, 2008.
Charge-carrier induced barrier-height reduction at organic heterojunction
S. W. Tsang, M. W. Denhoff, Y. Tao, and Z. H. Lu
In order to provide an accurate theoretical description of current densityvoltage (J-V) characteristics of an organic heterojunction device over a wide range of electric fields at various temperatures, it is proposed that an accumulation of charge carrier at the heterojunction will lead to a reducti ... [Phys. Rev. B 78, 081301 (2008)] published Fri Aug 1, 2008.
Electronic structure of the metallic ground state of La[sub 2 - 2x]Sr[sub 1 + 2x]Mn[sub 2]O[sub 7] for x [approximate] 0.59 and comparison with x = 0.36,0.38 compounds as revealed by angle-resolved photoemission
Z. Sun, J. F. Douglas, Q. Wang, D. S. Dessau, A. V. Fedorov et al.
Using angle-resolved photoemission spectroscopy, we present the electronic structure of the metallic ground state of LaSrMnO (x[approximate]0.59) and interpret the results in terms of first-principles band-structure computations, of which the generalized gradient approximation yields the best agreem ... [Phys. Rev. B 78, 075101 (2008)] published Fri Aug 1, 2008.
Area dependence of interlayer tunneling in strongly correlated bilayer two-dimensional electron systems at nu[sub T] = 1
A. D. K. Finck, A. R. Champagne, J. P. Eisenstein, L. N. Pfeiffer, and K. W. West
The area and perimeter dependences of the Josephson-like interlayer tunneling signature of the coherent nu=1 quantum Hall phase in bilayer two-dimensional electron systems is examined. Electrostatic top gates of various sizes and shapes are used to locally define distinct nu=1 regions in the same sa ... [Phys. Rev. B 78, 075302 (2008)] published Fri Aug 1, 2008.
In-plane conduction and c-axis polarization in the misfit-layered oxide [Bi[sub 2]Ca[sub 2]O[sub 4]][sub q]CoO[sub 2]
Makoto Maki, Koh-ichi Machida, Tadashi Mori, Terukazu Nishizaki, and Norio Kobayashi
We have used low-frequency dielectric measurements to study the evolution of anisotropic charge transport in misfit-layered oxides [BiCaO]CoO. Above ~60 K, the in-plane dc conductivity obeys the Arrhenius law and the dielectric polarization occurs along the c direction. We point out that this c-axi ... [Phys. Rev. B 78, 073101 (2008)] published Fri Aug 1, 2008.
Competition between Kondo and RKKY exchange couplings in Pu[sub 1 - x]Am[sub x] alloys: Density functional theory with static Hartree-Fock and dynamic Hubbard-I approximations
Myung Joon Han, Xiangang Wan, and Sergej Y. Savrasov
To clarify the role of the Kondo effect in screening local magnetic moments of plutonium 5f electrons as well as its competition to the RKKY interactions, we use a combination of density functional theory with static Hartree-Fock and dynamic Hubbard-I approximations to calculate the strength of both ... [Phys. Rev. B 78, 060401 (2008)] published Fri Aug 1, 2008.
Ferromagnetism in the multiband Kondo lattice model
A. Sharma and W. Nolting
The ferromagnetic spin-exchange interaction between the itinerant electrons and localized moments on a periodic lattice, studied within the so-called Kondo lattice model, is considered for multiband situation where the hopping integral is a matrix in general. The modified Ruderman-Kittel-Kasuya-Yosi ... [Phys. Rev. B 78, 054402 (2008)] published Fri Aug 1, 2008.
Low voltage organic light-emitting devices with triphenylphosphine oxide layer
Mi-Young Ha and Dae-Gyu Moon
We have developed low voltage driving organic light-emitting devices using triphenylphosphine oxide (PhPO) layers. The devices with a PhPO layer show high current density at a low voltage. For example, the current density of 20 mA/cm is achieved at a low voltage of 2.9 V for the device consisted o ... [Appl. Phys. Lett. 93, 043306 (2008)] published Fri Aug 1, 2008.
The origin of the hole injection improvements at indium tin oxide/molybdenum trioxide/N,N[sup [prime]]-bis(1-naphthyl)-N,N[sup [prime]]-diphenyl-1,1[sup [prime]]-biphenyl- 4,4[sup [prime]]-diamine interfaces
Hyunbok Lee, Sang Wan Cho, Kyul Han, Pyung Eun Jeon, Chung-Nam Whang et al.
We investigated the interfacial electronic structures of indium tin oxide (ITO)/molybdenum trioxide (MoO)/N,N-bis(1-naphthyl)-N,N-diphenyl-1,1-biphenyl-4,4-diamine (NPB) using in situ ultraviolet and x-ray photoemission spectroscopy to understand the origin of hole injection improvements in organic ... [Appl. Phys. Lett. 93, 043308 (2008)] published Fri Aug 1, 2008.
The origin of the hole injection improvements at indium tin oxide/molybdenum trioxide/N,N[sup [prime]]-bis(1-naphthyl)-N,N[sup [prime]]-diphenyl-1,1[sup [prime]]-biphenyl- 4,4[sup [prime]]-diamine interfaces
Hyunbok Lee, Sang Wan Cho, Kyul Han, Pyung Eun Jeon, Chung-Nam Whang et al.
We investigated the interfacial electronic structures of indium tin oxide (ITO)/molybdenum trioxide (MoO)/N,N-bis(1-naphthyl)-N,N-diphenyl-1,1-biphenyl-4,4-diamine (NPB) using in situ ultraviolet and x-ray photoemission spectroscopy to understand the origin of hole injection improvements in organic ... [Appl. Phys. Lett. 93, 043308 (2008)] published Fri Aug 1, 2008.
Effects of metal electrodes on the resistive memory switching property of NiO thin films
C. B. Lee, B. S. Kang, A. Benayad, M. J. Lee, S.-E. Ahn et al.
The effects of various metal electrodes on the resistive switching of NiO thin films were investigated. Contrary to the belief that Pt is used for its high work function, which enables Ohmic contact to p-type NiO, resistive switching was observed in films with Ta or Al electrodes with a low work fun ... [Appl. Phys. Lett. 93, 042115 (2008)] published Fri Aug 1, 2008.
Magnetoresistance near the ferromagnetic-paramagnetic phase transition in magnetic semiconductors
B. Brodowska, I. Kuryliszyn-Kudelska, T. Wojtowicz, M. Arciszewska, W. Dobrowolski et al.
Magnetic and transport properties of ferromagnetic semiconductors (FMSs) near the ferromagnetic-paramagnetic phase transition were studied in two classes of FMSs: in the IIIV-based InMnSb and GaMnAs epitaxial films and in IVVI-based SnMnTe and SnMnErTe alloys in bulk crystal form. Magnetoresistance ... [Appl. Phys. Lett. 93, 042113 (2008)] published Fri Aug 1, 2008.
Low voltage organic light-emitting devices with triphenylphosphine oxide layer
Mi-Young Ha and Dae-Gyu Moon
We have developed low voltage driving organic light-emitting devices using triphenylphosphine oxide (PhPO) layers. The devices with a PhPO layer show high current density at a low voltage. For example, the current density of 20 mA/cm is achieved at a low voltage of 2.9 V for the device consisted o ... [Appl. Phys. Lett. 93, 043306 (2008)] published Fri Aug 1, 2008.
Quantum Interference at the Twist Boundary in Graphene
S. Shallcross, S. Sharma, and O. A. Pankratov
We explore the consequences of a rotation between graphene layers for the electronic spectrum. We derive the commensuration condition in real space and show that the interlayer electronic coupling is governed by an equivalent commensuration in reciprocal space. The larger the commensuration cell, th ... [Phys. Rev. Lett. 101, 056803 (2008)] published Fri Aug 1, 2008.
Nonlinear Excitation of Surface Plasmon Polaritons by Four-Wave Mixing
Stefano Palomba and Lukas Novotny
We demonstrate nonlinear excitation of surface plasmons on a gold film by optical four-wave mixing. Two excitation beams of frequencies omega and omega are used in a modified Kretschmann configuration to induce a nonlinear polarization at a frequency of omega=2omega-omega, which gives rise to surfac ... [Phys. Rev. Lett. 101, 056802 (2008)] published Fri Aug 1, 2008.
Electronic Coherence in delta-Pu: A Dynamical Mean-Field Theory Study
C. A. Marianetti, K. Haule, G. Kotliar, and M. J. Fluss
A combination of density functional theory and the dynamical mean-field theory (DMFT) is used to calculate the magnetic susceptibility, heat capacity, and the temperature dependence of the valence band photoemission spectra for delta-Pu. We predict that delta-Pu has a Pauli-like magnetic susceptibil ... [Phys. Rev. Lett. 101, 056403 (2008)] published Fri Aug 1, 2008.