Characterization of InGaSb/GaSb p-n photodetectors in the 1.0- to 2.4-μm wavelength range

Optical and electrical characteristics of InGaSb p-n photodetectors are presented at different temperatures. The device structures were grown on GaSb substrates using organic metal vapor phase epitaxy. Spectral calibration indicates peak responsivity around 2 µm, equivalent to 58% quantum efficiency, with 2.3-µm cutoff at room temperature. Reducing the device temperature increases the responsivity and shifts the cutoff wavelength to a shorter value. Current voltage measurements at different temperatures indicate that tunneling is the primary leakage current mechanism. Assuming Johnson limited performance, detectivity calculations resulted in 4×1010 cm Hz1/2/W indicating that InGaSb is a superior material for 2-µm detection applications.