PDF(Sci-hub)
Abstract：
We systematically study, by using first-principles calculations, stabilities, electronic properties, and optical properties of GexSn1-xSe alloy made of SnSe and GeSe monolayers with different Ge concentrations x = 0.0, 0.25, 0.5, 0.75, and 1.0. Our results show that the critical solubility temperature of the alloy is around 580 K. With the increase of Ge concentration, band gap of the alloy increases nonlinearly and ranges from 0.92 to 1.13 eV at the PBE level and 1.39 to 1.59 eV at the HSE06 level. When the Ge concentration x is more than 0.5, the alloy changes into a direct bandgap semiconductor; the band gap ranges from 1.06 to 1.13 eV at the PBE level and 1.50 to 1.59 eV at the HSE06 level, which falls within the range of the optimum band gap for solar cells. Further optical calculations verify that, through alloying, the optical properties can be improved by subtle controlling the compositions. Since GexSn1-xSe alloys with different compositions have been successfully fabricated in experiments, we hope these insights will contribute to the future application in optoelectronics.
摘要：
我们系统地研究,通过使用第一原理计算，稳定性,电子性质，由不同Ge浓度x=0.0、0.25、0.5、0.75和1.0的SnSe和GeSe单层制成的GexSn1-xSe合金的光学性能。结果表明,随着Ge浓度的增加,合金的临界溶解温度在580K左右,合金的带隙非线性增加，在PBE能级为0.92至1.13eV，在HSE06能级为1.39至1.59eV。当Ge浓度x大于0.5时，合金转变为直接带隙半导体；在PBE能级，带隙范围为1.06至1.13eV，在HSE06能级，带隙范围为1.50至1.59eV，落在太阳能电池的最佳带隙范围内。进一步的光学计算证明，通过合金化，光学性能可以通过微妙的控制组成来改善。由于具有不同成分的GexSn1-xSe合金已在实验中成功制造，我们希望这些见解将有助于未来在光电子学中的应用。
