Homogeneity and tolerance to heat of monolayer MoS2 on SiO2 and h-BN

Abstract

We investigated the homogeneity and tolerance to heat of monolayer MoS₂ using photoluminescence (PL) spectroscopy. For MoS₂ on SiO₂, the PL spectra of the basal plane differ from those of the edge, but MoS₂ on hexagonal boron nitride (h-BN) was electron-depleted with a homogeneous PL spectra over the entire area. Annealing at 450 °C rendered MoS₂ on SiO₂ homogeneously electron-depleted over the entire area by creating numerous defects; moreover, annealing at 550 °C and subsequent laser irradiation on the MoS₂ monolayer caused a loss of its inherent crystal structure. On the other hand, monolayer MoS₂ on h-BN was preserved up to 550 °C with its PL spectra not much changed compared with MoS₂ on SiO₂. We performed an experiment to qualitatively compare the binding energies between various layers, and discuss the tolerance of monolayer MoS₂ to heat on the basis of interlayer/interfacial binding energy.