Deep-level traps induced dark currents in extended wavelength In_xGa_(1-x)As/lnP photodetector

摘要

The dark current mechanism of extended wavelength In_xGa_(1-x)As photo-detectors is still a debated issue. In this paper, the deep-level transient spectroscopy (DLTS) and dark current characteristics of In_xGa_(1-x)AsInP detectors are investigated. Using trap parameters obtained from DLTS measurement, the device simulations of current-voltage characteristics are carried out by,Silvaco Altas. The results reveal that the dark current at the low reverse bias voltage is associated with deep level trap induced trap assisted tunneling and Shockley-Read-Hall generation mechanism. The reduction of the deep level trap concentration in In_xGa_(1-x)As absorption layer could dramatically suppress the dark current near zero bias in extended wavelength In_xGa_(1-x)As/InP detectors.