摘要
Layered growth of molybdenum disulphide (MoS 2 ) was successfully achieved by pulsed laser deposition (PLD) method on c -plane sapphire substrate. Growth of monolayer to a few monolayer MoS 2 , dependent on the pulsed number of excimer laser in PLD is demonstrated, indicating the promising controllability of layer growth. Among the samples with various pulse number deposition, the frequency difference (A 1g -E 1 2g ) in Raman analysis of the 70 pulse sample is estimated as 20.11 cm -1 , suggesting a monolayer MoS 2 was obtained. Two-dimensional (2D) layer growth of MoS 2 is confirmed by the streaky reflection high energy electron diffraction (RHEED) patterns during growth and the cross-sectional view of transmission electron microscopy (TEM). The in-plane relationship, (0006) sapphire//(0002)MoS 2 and [2110] sapphire//[0110]MoS 2 is determined. The results imply that PLD is suitable for layered MoS 2 growth. Additionally, the oxide states of Mo 3d core level spectra of PLD grown MoS 2 , analysed by X-ray photoelectron spectroscopy (XPS), can be effectively reduced by adopting a post sulfurization process.