Comprehensive study on electronic structures of SiGe/ Ga2SeTe vdW heterobilayer

Janus two-dimensional (2D) materials have been extensively studied in recent years due to their intriguing properties. Herein, we have performed the first principles calculations to investigate optoelectronic properties of heterobilayer which have formed with monolayer SiGe and Janus Ga2SeTe. We have examined the electronic and optical properties of SiGe/Ga2SeTe heterobilayers under the biaxial strain. Similarly to graphene-based heterobilayers, we reveal that the Dirac-cone of monolayer SiGe has been preserved in both pristine and strained heterobilayers. Hence, we have also examined the Schottky barrier height (SBH) of the SiGe/Ga2SeTe heterobilayer and have found it to be n-type for the pristine case. We have depicted that the SBH of strained heterobilayer is transformed to p-type or ohmic contact. In order to carry out a comprehensive electronic study, we have examined three twisted systems that we have regarded are root 7 x root 7, root 13 x root 13, and root 19 x root 19, accordingly, we have determined the interlayer misorientation. Additionally, the entire spectrum of the imaginary part of the dielectric function has slightly shifted to infra-red (ultraviolet) regions in the presence of tensile (compressive) strains.

Automated summary

In this study, the optoelectronic properties of heterobilayers formed with monolayer SiGe and Janus Ga2SeTe have been investigated using first principles calculations. It was found that the Dirac cone of monolayer SiGe was preserved in both pristine and strained heterobilayers. The Schottky barrier height of the SiGe/Ga2SeTe heterobilayer was initially n-type and became p-type or ohmic contact under strain. Three twisted heterobilayer systems were also examined, and the interlayer misorientation was determined. In the presence of tensile or compressive strains, the imaginary part of the dielectric function spectrum slightly shifted to the infrared or ultraviolet regions, respectively.