Metal-semiconductor-metal photodetectors on a GeSn-on-insulator platform for 2 m applications

In this work, the metal-semiconductor-metal photodetectors were demonstrated on the Ge0.91Sn0.09-on-insulator (GeSnOI) platform. The responsivity was 0.24 and 0.06 A/W at wavelengths of 1,600 and 2,003 nm, respectively. Through a systematic study, it is revealed that the photodetectors can potentially detect the wavelength beyond 2,200 nm. The dark current density was measured to be 4.6 A/cm2 for GeSnOI waveguide-shaped photodetectors. The 3dB bandwidth was observed to be 1.26 and 0.81 GHz at 1,550 and 2,000 nm wavelengths, respectively. This work opens up an opportunity for low-cost 2 µm wavelength photodetection on the GeSn/Ge interface-free GeSnOI platform.Ministry of Education (MOE)National Research Foundation (NRF)Submitted/Accepted versionThis work was supported by the National Research Foundation, Singapore, under its Competitive Research Program (CRP Award NRF-CRP19-2017-01), Ministry of Education AcRF Tier 2 (T2EP50121-0001 (MOE-000180-01)), and Ministry of Education AcRF Tier 1 (2021-T1-002-031 (RG112/21))