Si-based GeSn photodetectors towards mid-infrared imaging applications

摘要： The GeSn detector offers the high-performance Si-based infrared photodetectors with complementary metal-oxide-semiconductor (CMOS) technique compatibility. In this work, we reports a comprehensive study of Si-based GeSn mid-infrared photodetectors, which includes: i) 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 μm. The maximum D* of 1.1×1010 cm?Hz1/2?W-1 measured at 77 K is comparable to that of commercial extended-InGaAs detectors; ii) 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. This work is a major step towards Si-based mid-infrared photodetectors for imaging applications.