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

The growth of monolayer MoS₂ crystals on chemomechanically polished (CMP) N-polar GaN using PTAS-assisted chemical vapor deposition is demonstrated. The formation of monolayer MoS₂ was initially prevented by the as-grown GaN's large surface roughness. CMP reduces the roughness to 250 pm, enabling monolayer MoS₂ 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 MoS₂ monolayers can be obtained on N-polar GaN for future high-speed optoelectronic and quantum sensing applications. [ABSTRACT FROM AUTHOR]