ANALYSIS OF NORMAL-INCIDENT ABSORPTION IN A PROPOSED P-TYPE VERY-NARROW-QUANTUM-WELL INFRARED PHOTODETECTOR

A p-type very-narrow-quantum-well infrared photodetector is proposed a nd studied in this letter. Direct transitions between extended-state h eavy-hole-like subbands and bound-state light-hole-like subbands are u tilized. A first-principles k.p calculation of normal-incident absorpt ion is performed with no adjustable parameter. In spite of quantum wel ls only 17 angstrom wide, integrated absorption is found to be stronge r in the proposed structure (at T = 77 K, from lambda = 8 mum to lambd a = 10 mum) than in a conventional p-type quantum-well infrared photod etector with the same cutoff wavelength. The integrated responsivity i s estimated to be more than twice as high, while the integrated shot-n oise-limited detectivity can be improved by a factor of 2. The propose d structure may also be implemented as a two-color photodetector.