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

Abstract

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.

CVD-Grown Monolayer MoS2 and GaN Thin Film Heterostructure for a Self-Powered and Bidirectional Photodetector with an Extended Active Spectrum

“…The peak separation of ∼19.7 cm –1 unequivocally validates the existence of a monolayer of MoS 2 . Furthermore, the Lorentzian profile fitted full width at half-maximum (fwhm) values were found to be approximately 8 cm –1 for the E 2g peak and around 9 cm –1 for the A 1g peak, consistent with the previously reported for epitaxially grown MoS 2 on GaN . Moreover, the MoS 2 E 2g peak was found to be in the same position in both the MoS 2 /GaN heterostructure and the bare MoS 2 (MoS 2 grown on SiO 2 ), as illustrated in Figure S2(b), SI.…”

“…21 Furthermore, the Lorentzian profile fitted full width at half-maximum (fwhm) values were found to be approximately 8 cm −1 for the E 2g peak and around 9 cm −1 for the A 1g peak, consistent with the previously reported for epitaxially grown MoS 2 on GaN. 35 Moreover, the MoS 2 E 2g peak was found to be in the same position in both the MoS 2 /GaN heterostructure and the bare MoS 2 (MoS 2 grown on SiO 2 ), as illustrated in Figure S2(b), SI. However, an interesting observation pertains to the MoS 2 A 1g peak, which exhibits a blue shift for the heterostructures compared to its bare counterpart.…”

Growth of Wide-Bandgap Monolayer Molybdenum Disulfide for a Highly Sensitive Micro-Displacement Sensor

“…Raman spectroscopy is a kind of accurate, rapid, and non-destructive detection method for finding the composition and molecular structure of substances using the Raman scattering effect. As shown in Figure 5c, Raman spectroscopy of the obtained wide-bandgap MoS 2 was performed at room temperature using a 532 nm laser line, which showed two peaks at 386 cm −1 and 403 cm −1 , corresponding to the two molecular oscillations E 2g 1 and A 1g of monolayer MoS 2 reported in the literature, respectively [36]. Meanwhile, the wave-number difference between the two peaks was less than 20 cm −1 , indicating that the prepared MoS 2 was a single layer [37].…”