Bistable quantum-well infrared phototransistors (BQWIPs) utilising int
ersubband electron phototransitions and resonant-tunnelling injection
are considered. The mechanisms of the bistability effect are discussed
. An analytical model of the BQWIP operation is proposed and used to d
erive its characteristics. To optimise the BQWIP performance the param
eters of the hysteresis loops in the BQWIP characteristics are obtaine
d as functions of its physical parameters.