95%Ar+5%H2气氛退火对Ag/MoS2和Ag/BN/MoS2薄膜形貌和结构的影响

Effect of Annealing in 95% Ar + 5%H2 on the Morphology and Structure of Ag/MoS2and Ag/BN/MoS2Thin Films

采用射频(RF)磁控溅射在室温下连续逐层沉积,然后在95%Ar+5%H 2混合气氛中进行500℃低温退火制备了Ag/MoS2和Ag/BN/MoS2纳米薄膜,采用拉曼光谱(Raman)、X射线光电子能谱(XPS)和原子力显微镜(AFM)对其结构、组成和表面形貌进行了研究。结果表明:所制备的纳米膜均匀连续,界面紧密且清洁。95%Ar+5%H 2混合气氛中退火能强烈影响顶部MoS2层的形貌并有效去除MoS2中的杂质氧改善其结晶性、稳定性和结构完整性;顶部MoS2层在沉积态时呈细小颗粒状,退火后呈片层状和颗粒状混合形态,特别是引入BN层后促进了其向更大更薄的片状转变,且MoS2薄膜由块状变成类层状结构。另外,电性能表征显示Ag/MoS2具有良好的欧姆接触且电阻率低,引入BN层使得Ag与BN以及BN与MoS2的界面处产生肖特基势垒从而使Ag/BN/MoS2具有整流特性。

Ag/MoS2 and Ag/BN/MoS2 nano films were prepared by radio frequency(RF)magnetron sputtering via successive layer-by-layer deposition at room temperature,and then annealed at 500℃in 95%Ar+5%H 2 mixed atmosphere.The structure,composition and surface morphology were studied by Raman spectrum,X-ray photoelectron spectroscopy(XPS)and atomic force microscopy(AFM).The results show that the prepared nano films have uniform continuous surface and tightly clean interface.Annealing in 95%Ar+5%H 2 mixed atmosphere strongly influences the morphology of the top MoS2 layer,it also effectively removes the impurity oxygen in MoS2 and improves its crystallinity,stability and structural integrity.The MoS2 layer is composed of fine particles in the as-deposited state.After being annealed,especially inserting a BN layer,the morphology of the top MoS2 layer changes from particle to a mixture of particle and lamellae,and the lamellae become large and thin.The results of electrical property test show that Ag/MoS2 exhibits good ohmic contact and low resistivity,and the insertion of the BN layer results in Schottky barrier at the interface between Ag to BN and BN to MoS2,respectively;consequently,apparent rectifying characteristics are obtained.