Two-mode InGaSb/GaSb strained-layer superlattice infrared photodetector

An interesting two-mode photodetector was constructed using an In/sub 0.19/Ga/sub 0.81/Sb/GaSb strained-layer superlattice (SLS). Such a structure is, at the same time, of type I for heavy hole and type II for light hole. The mini-subbands of this In/sub 0.19/Ga/sub 0.81/Sb/GaSb SLS are calculated using the modified Kronig-Penney model, as a function of well width at 300 K. A ten-period In/sub 0.19/Ga/sub 0.81/Sb/GaSb SLS structure can be applied as a two-mode photodetector with near-zero and reverse bias. This phenomenon can be proved by the spectral response of the structure grown by low-pressure metalorganic chemical vapor deposition (MOCVD). The wavelengths of dominant absorption peaks are 1.92 and 1.77 mu m at near-zero and reverse bias, respectively. The experimental data are in good agreement with the theoretical deductions.<>