Band and luminescence regulation of SiGeSn ternary alloy: A first-principles investigation

●The band and luminescence regulation of SiGeSn are investigated using a first-principles method.●The best way to maintain a direct bandgap is to simultaneously increase the Si and Sn concentrations.●The variation laws of the positive gain region and optical gain of SiGeSn are described in detail.●For Siy(y=0~0.21)GezSnx(x=0.1~0.31), there are two maximum optical gain regions around Ge0.9Sn0.1 and Si0.17Ge0.56Sn0.27.