Silicon-based Ge_(0.89)Sn_(0.11) photodetector and light emitter towards mid-infrared applications

摘要

The GeSn alloy with Sn composition of 11% has been grown using an industry standard reduced-pressure chemical vapor deposition reactor in a single run epitaxy. Low-cost commercially available GeH_4 and SnCl_4 were used as Ge and Sn precursors, respectively. The material characterization showed that the threading dislocations were trapped in the Ge/GeSn interface and do not propagate to the GeSn layer, resulting in high quality material. The temperature-dependent photoluminescence study revealed that the direct bandgap GeSn alloy was achieved, as the emission intensity significantly increased at low temperature. The sample was than fabricated into photoconductive detectors and waveguide lasers. For the photodetector, the spectral response wavelength cutoff at 3.0 μm was observed. The specific detectivity of 3.5 × 10~(10) cm ?Hz~(1/2)W~(-1) was achieved, which is close to that of market dominating InGaAs photodetectors that are operating in the same wavelength range; For the waveguide laser, the lasing threshold pumping power density of 86.5 kW/cm~2 at 10 K and the highest operating temperature of 110 K were obtained. Furthermore, the characteristic temperature was evaluated as 65 K.