Silicene/GaAs van der Waals heterostructure for optoelectronic applications

Two-dimensional (2D) materials have shown promising results for optoelectronic applications with ever-growing applications. The performance of existing III–V optoelectronic devices can be improved by formulating heterostructures between 2D materials and III–V materials. In this work, the first-principles calculation of silicene/GaAs heterostructure is presented. Interfacial effects are very critical for optoelectronic applications. Such effects have not been explored yet for silicene/GaAs heterostructure. Effects like the diffusion/adsorption of Ga and As atoms to/on silicene from the GaAs layer are investigated, and the effect of this diffusion/adsorption  on the electronic properties of silicene is analyzed. An opening of the bandgap in silicene is observed under the diffusion of Ga/As to the silicene layer. A bandgap of 0.38 eV/0.44 eV is observed in Ga-doped/As-adsorbed silicene. Both the cases of doping and adsorption are considered in this study. The possibility of diffusion of the Ga atom is more than that of the As atom. Furthermore, carriers (electrons) flow from the GaAs layer to the silicene layer due to a built-in electric field at the interface. This built-in electric field can help separate the photogenerated carriers, which can eventually advance the performance of the GaAs optoelectronic devices.