Electrically Tunable Light Detector
Original Publication Date: 1983-Oct-01
Included in the Prior Art Database: 2005-Feb-07
An electrically tunable light detector may be provided by appropriate biasing of the structure of the figure. If gate #2 is so biased as to turn on the silicon under it (invert the surface) and gate #1 is biased so that the region under it is depleted, the depleted region will act as a barrier for electrons in the surface. The height of the barrier is just the difference of the Fermi level less the conduction band energy in the two regions. Both may be modulated by the gate voltages. For instance, at 4.2K if gate #2 is biased to inversion, then the Fermi level will lie 10-80 meV above the conduction band edge in practice. However, the Fermi level under gate #1 can be varied between about 1.1 and some arbitrarily small value less than 0.1 meV below the conduction band. Therefore, the barrier can be varied by about 1.1 eV.