Study of the effect of temperature on the detectivity and sensitivity of GeSn-based heterojunction phototransistor for mid-wave infrared applications

Abstract

In an effort to find the optimal mid-wave infrared (MWIR) photodetector, Si-based GeSn heterojunction phototransistors (HPTs) were studied. The figure of merit (FOM) and noise-equivalent-power (NEP) of the proposed device were calculated the first time at different operating temperatures for MWIR applications. In addition, the impact of operating frequency on the detectivity and sensitivity of the device was also studied. A high detectivity of $${>10}^{9}\mathrm{ cm}{\mathrm{Hz}}^{1/2}/\mathrm{W}$$ , a low NEP of < $${10}^{-12}{\mathrm{WHz}}^{-1/2}$$ , and a low rise time of $$\sim 7.2 \mathrm{ps}$$ were achieved at 300 K. These results indicate that the proposed GeSn HPTs can be used as an optoelectronic converter in a high-speed and low noise photodetection system.