氮掺杂单层石墨烯上无中间层沉积高质量氮化镓

Abstract

GaN on graphene/Al 2 O 3 substrates grown via van der Waals epitaxy compensates for the deficiencies and defects caused by metal-organic chemical vapor deposition (MOCVD) on substrates with significant mismatches to GaN. However, the absence of dangling bonds on graphene leads to insufficient nucleation sites; hence, a thin layer of AlN or ZnO nanowalls should be deposited on graphene as an intermediate layer. In this work, high-quality GaN crystals with a low biaxial compressive stress of 0.023 GPa and low screw dislocation density of 9.76 × 10 7 cm −2 were successfully synthesized by MOCVD on nitrogen-doped graphene without a buffer layer. First-principles calculations demonstrated significant improvement in the adsorption energy of the Ga atom on the surface of nitrogen-doped graphene compared with that of pristine graphene, in agreement with the experimental observations of nucleation. In most cases, GaN films were obtained by forming C-Ga-N and N-Ga-N configurations via atomic nitrogen pretreatment on monolayer graphene. Therefore, it is hoped that the efficient method of atomic modulation of high-quality GaN films grown on nitrogendoped graphene via interface manipulation used in this work will promote the industrial development of innovative semiconductor devices.