Tunable electronic properties in two-dimensional h-Si/GaP van der Waals heterobilayer

In recent days, two-dimensional (2D) silicene, a close neighbor to graphene and germanene, has garnered massive research attention for its promising electronic properties and structural stabilities. However, the inherent zero bandgaps is a major limitation of the silicene-based materials to incorporate them into the manufacturing of nanoelectronic devices. As a step to solving this problem, in this research, we presented a first principle investigation of group IV honeycomb silicene monolayer stacked above 2D gallium phosphide (h-Si/GaP) monolayer. The research is carried out sequentially in order to examine the tunable structural and electrical aspects of the h-Si/GaP heterobilayer structure. The proposed 2D h-Si/GaP exhibits a direct 356 meV bandgap at the K-point. This bandgap is tailorable between 0 meV to 536 meV by modifying the interval between the monolayer of silicene and Gallium phosphide. The study into the charge density states and the charge density difference reveals that the 2D-GaP monolayer acts as a very good substrate, making the charge carriers move across the silicene layer only with carrier mobility of 1.13 × 10⁵ cm²V⁻¹s⁻¹. These behavioral phenomena make the proposed novel h-Si/GaP heterobilayer a promising material for high speedy, tunable, and structurally stable nanoelectronic and spintronic devices.