Flexible Amorphous GeSn MSM Photodetectors.

We demonstrate amorphous Ge_0.92Sn_0.08 surface illuminated metal–semiconductor–metal (MSM) photodetectors on flexible substrates for visible wavelength. Photodetection at 633 nm is achieved with an I–V response up to 10^–4 A for a 2 V bias voltage. Different evaporation rate effects on the amorphous GeSn MSM photodetector are examined. Bending/strain effects on device performance were studied by evaluating the current density versus voltage characteristics. Amorphous GeSn thin film deposition on polyethylene terephthalate flexible substrate and Ni/Au–GeSn–Ni/Au MSM photodetector finger pattern deposition were performed via thermal evaporation. Photocurrent and dark current densities of amorphous GeSn MSM photodetectors were obtained at 1.36 A/cm² and 0.24 A/cm², respectively, where the photocurrent to dark current contrast ratio was found to be equal to 5.6. We also examined the evaporation rate, strain, and bending effect. [ABSTRACT FROM AUTHOR]