Homogeneity and tolerance to heat of monolayer MoS on SiO and h-BN.

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