Si-based GeSn photodetectors towards mid-infrared imaging applications

TL;DR

This study advances Si-based GeSn photodetectors for mid-infrared imaging by demonstrating extended wavelength detection, improved surface passivation, and comparable imaging quality to commercial detectors.

Contribution

It introduces GeSn photodetectors with extended wavelength range, enhanced surface passivation techniques, and demonstrates their practical imaging capabilities.

Findings

Extended detection wavelength up to 3.65 μm.

Maximum D* of 1.1x10^10 cmHz^(1/2)W^(-1).

Mid-infrared images comparable to commercial PbSe detectors.

Abstract

This paper reports a comprehensive study of Si-based GeSn mid-infrared photodetectors, which includes: 1) the demonstration of a set of photoconductors with Sn compositions ranging from 10.5% to 22.3%, showing the cut-off wavelength has been extended to 3.65 um. The measured maximum D* of 1.1x10^10 cmHz^(1/2)W(-1) is comparable to that of commercial extended-InGaAs detectors; 2) the development of surface passivation technique on photodiode based on in-depth analysis of dark current mechanism, effectively reducing the dark current. Moreover, mid-infrared images were obtained using GeSn photodetectors, showing the comparable image quality with that acquired by using commercial PbSe detectors.