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.