We investigated the conduction mechanism and performance of GaAs-A1GaAs
quantum-well infrared photodetectors and proposed a conduction model
consisting of Poole-Frenkel-like emission from wells and carrier relaxation
wells. The model agrees with the measured photocurrent and dark current. The
detector's noise current is given by a simple shot noise formula. Analysis
has shown that the photocurrent and the noise current are inversely
proportional to the barrier width, while the dark current is inversely
proportional to the square of the barrier width.