Quantum Tunneling Transistor
Schematic diagram of a quantum tunneling transistor, an on-off switch that exploits an electron's ability to pass through normally impenetrable energy barriers.
The various contacts and gates adjust the voltage between the upper quantum well (labelled "top QW") and the lower quantum well ("bottom QW"), both made of gallium arsenide and having thicknesses of just 150 Angstroms (where 1 Angstrom
equals 10-10 meters).
Adjusting the voltage in the right way allows the electrons in the top QW to "tunnel through" an ordinarily insurmountable barrier (made of
aluminum gallium arsenide, depicted as a sawtoothed energy barrier in the leftmost diagram) to the bottom
QW. Tunneling occurs
when the top QW and bottom QW accept electrons with the same energy and momentum states. (Figure courtesy Sandia National Laboratories)
This research was described at the 1997 IEEE International Electron Device Meeting in Washington, DC, December 7-10, 1997.
Link to Physics News Update Item on this research