Quantum-well infrared phototransistor with pHEMT structure

Abstract

A quantum-well infrared phototransistor with a pseudomorphic high-electron mobility transistor (pHEMT) structure is presented. The proposed phototransistor uses four periods of a GaAs/Al0.3Ga0.7As (50 angstrom/120 angstrom) quantum-well absorption region, as well as an In0.15Ga0.85As quantum well conducting channel under the absorption layer. The phototransistor shows a large responsivity of 140 A/W around 6 mu m at 23 K (for a cutoff wavelength of 7.5 mu m). The relation between the photoconductive gain and the transconductance of the pHEMT structure is also investigated.