PHOTOCONDUCTIVE MATERIALS AND DEVICES WITH INTERNAL PHOTOCONDUCTIVE GAIN

摘要

The invention provides a new class of photoconductive materials and devices, and methods for obtaining high internal photoconductive gain. The devices include a semiconductor or material with an electronic band gap provided in a confined geometry and which exhibits multi-exciton generation (MEG) when illuminated with photons with energies above the threshold for MEG. Due to carrier-carrier Coulombic interactions, multi-excitons within the confined material efficiently recombine via Auger recombination, in which a carrier from one exciton is excited to a higher energy level relative to the band edge. Carriers excited by Auger recombination are subsequently trapped by trap states that capture carriers excited high above the band edge more efficiently than carriers near the band edge. Carriers trapped by the trap states allow for the collection and recirculation of untrapped carriers of opposite charge when used as a photoconductive device, producing high internal photoconductive gain.