Graphene direct growth by microwave PECVD on h-BN films deposited by reactive HIPIMS

Abstract This research explores the synthesis of graphene using microwave plasma-enhanced chemical vapor deposition (PECVD) on a hexagonal boron nitride interlayer deposited by reactive high-power impulse magnetron sputtering. The effects of h-BN interlayer composition and thickness on the graphene structure, morphology, and electronic properties were investigated using Raman scattering spectroscopy, atomic force microscopy, and conductive atomic force microscopy. The electrical and photoelectrical characteristics of the graphene/Si(100) and graphene/h-BN/Si(100) diodes were studied. It was revealed that graphene self-doping effects, primarily originating from substrate-induced charge transfer, can be partially controlled, and that the dominant defect type of graphene can be changed by varying the boron interlayer thickness. The graphene layers synthesized on the SiO 2 film were substantially smoother than those grown on the boron nitride films. Graphene grown on h-BN had a substantially greater surface current than graphene synthesized on the SiO 2 layer. There was no relationship between graphene self-doping and graphene surface conductivity. Nevertheless, it should be noted that reduced graphene self-doping was achieved even though the surface roughness of the h-BN film was significantly greater than that of the SiO 2 film or Si(100), and B–H and C–H bonds were present in some h-BN films. Tunneling is the primary reverse current charge transfer mechanism, similar to graphene/Si(100) diodes, and h-BN interlayers cannot decrease the reverse dark current. Despite these circumstances, the insertion of the h-BN interlayer resulted in a significant increase in the photocurrent, short-circuit current, and open-circuit voltage compared to those of the graphene/Si(100) heterojunction. The observed effects of the h-BN interlayer on the graphene/Si(100) diode properties were explained by the competition between the effects of the different h-BN film compositions, thicknesses, and roughness on the one hand and the influence of the graphene structure and electronic properties.