Chemical Vapor Deposition of Monolayer MoS2 on Chemomechanically Polished N-Polar GaN for Future 2D/3D Heterojunction Optoelectronics

The growth of monolayer MoS 2 crystals on chemomechanically polished (CMP) N-polar GaN using PTAS-assisted chemical vapor deposition is demonstrated. The formation of monolayer MoS 2 was initially prevented by the as-grown GaN’s large surface roughness. CMP reduces the roughness to 250 pm, enabling monolayer MoS 2 triangles with edge lengths of 30 μm, a Raman peak separation of <20 cm –1, and an optical bandgap of 1.81 eV, which is on par with those obtained on smooth Ga-polar GaN. It is thus demonstrated that high-quality MoS 2 monolayers can be obtained on N-polar GaN for future high-speed optoelectronic and quantum sensing applications.