Enhanced photoconductive gain in quantum-well infrared photodetectors

A quantum-mechanical scattering theory approach is taken to evaluate the capture probability from the continuum into the quantum wells in quantum-well infrared photodetectors. The calculations show that the capture probability is dependent on the well width, the barrier height, and bias. An additional tunnel barrier is introduced to disturb the continuum levels near the top of the quantum well. It is shown that this can be optimized to reduce the capture probability and thus increase the photoconductive gain of the device.