The effect of compressive strain on the performance of p-type quantum-well infrared photodetectors

A detailed study of the performance of compressively strained p-type III-V quantum-well infrared photodetectors (p-QWIP's) is presented in this work, Three device structures composed of InGaAs-GaAs, InGaAs-AlGaAs, and InGaAs-AlGaAs-GaAs for normal incidence absorption have been fabricated and analysed, with the results being compared with similar reported unstrained p-QWIP's, In all three QWIP structures, the quantum-well layers are under biaxial compressive strain ranging from -0.8% to -2.8%, while the barrier layers are lattice-matched to the substrate, The detection peaks of the quantum-well infrared photodetectors ranged from 7.4 to 10.4 mu m, The detectors utilized the bound-to-continuum, bound-to quasi-bound, and step bound-to-miniband intersubband transitions for infrared detection, The results showed that responsivities of up to 90 mA/W and detectivities from 10(9) to over 10(10) cm root Hz/W are achieved under moderate applied bias and at reasonable operating temperatures (from 60 to 80 K), demonstrating the viability of the strained-layer p-doped quantum-well infrared photodetectors for staring focal plane array applications.