Semiconductor Electronic Device

Density functional theory study of semiconductor bandgap regulation

The zero-band gap characteristic of graphene makes it impossible to turn off the conductivity at a specific limit. Because a certain band gap can greatly enhance the potential of graphene in a variety of applications, the widening of the graphene band gap has gained widespread attention. Silicon is the main material in the semiconductor industry. Due to the compatibility between graphene and silicon, the adsorption of graphene on silicon substrates is particularly attractive for its future applications.

The adsorption configuration, adsorption energy and band structure of graphene (including monolayer and bilayer structures) on crystalline silicon (111)/(100) with or without surface hydrogen passivation were compared in detail by density functional theory (Dmol3) calculations. It is found that the interaction between monolayer graphene and hydrogen-passivated crystalline silicon surface is very weak, and the effect on the band gap of graphene is negligible. Due to the destruction of symmetry, the band gap of double-layer graphene will be opened to a certain extent when it is adsorbed on the surface of hydrogen-passivated crystalline silicon. This study provides strong theoretical support for the design of devices based on graphene and crystalline silicon, and enhances the application potential of graphene in the field of optoelectronics.

ACS Nano 9,8562-8568 (2015)