PHOTOVOLTAIC QUANTUM-WELL INFRARED PHOTODETECTORS - THE 4-ZONE SCHEME

We have investigated a particular class of photovoltaic quantum well i ntersubband photodetectors. Each period of the active region in these structures consists of four zones, namely an excitation zone, a drift zone, a capture zone, and a tunneling zone. The devices show pronounce d photovoltaic behavior and high detectivities. In particular, the res ponsivity without external bias is substantially enhanced if resonant carrier capture is achieved due to an appropriate design of the captur e zone. (C) 1997 American Institute of Physics.