Study On Chemical Vapor Deposition MoS₂ And Its Sensor

As the development of more than Moore, many effort has been focused on the novel material study in recent years. The discovery of graphene as well as its large-scale production and application open up a new field of two dimensional (2D)-materials. Due to its special structure and unique physical properties, MoS2 as the representative of graphene-like materials overcome the disadvantage of zero band gap. However, the preparation methods of MoS2 are the key problems to hinder its research and industrialization development. In this thesis, MoS2 preparation via Chemical Vapor Deposition(CVD) were studied. The main purpose is to establish an effective and reliable way to prepare MoS2 and find its application in humidity sensors. The main content of this thesis is as following:Firstly, two substrate placement schemes, Le.,face-up and face-down, were considered in MoS2 CVD growth. The parameters related to these two schemes were further studied and discussed systemically to improve the material performance. MoS2 samples with mono- or few layers had been prepared successfully.Secondly, for the first time the face-slant substrate placement scheme was introduced into our CVD system, and the mono-layered MoS2 was successfully synthesized. As the substrate was slanting, the large-sized monolayer MoS2 can be grown with the reduced temperature and the improved yield. The influence of different process parameters on the MoS2 growth was also studied.Thirdly, with in situ growth MoS2 as sensing element, the humidity sensor was fabricated for the first time. The parameters like humidity response, hysteresis, response time and stability were studied. The results indicated that the MoS2 is a good sensing material for humidity.