过渡金属二硫化物二维纳米结构的可控制备及其表面静电性质研究

Monolayer or few-layer graphene-like transition metal dichalcogenides are new two-dimensional layered materials, which is a new hotspot in recent nano-research fields. Two-dimensional molybdenum disulfide and tungsten disulfide nanomaterials have exhibited excellent optical and electronic properties because of their unique electronic band structures, which are expected to give rise to broad and important applications in micronano-electronic and optoelectronic devices. However, the controllable preparation of transition metal dichalcogenide nanostructures is still a big challenge, and the current studies on the fundamental physical properties of this kind of material are mainly focused on the electrical transport and optical properties. Surface electrostatic properties of these materials, such as surface potential and charge distributions, have not received much attention until now. In this project, we aim to achieve the controllable preparation of two-dimensional MoS2 and WS2 nanostructures through systematic research by employing vapor phase deposition method. The surface electrostatic properties of transition metal dichalcogenides with different nanostructures will be extensively explored by using Kelvin probe force microscopy. The influence of different humidities on the surface electrostatic properties will be systematically investigated, and the corresponding mechanism will be illuminated. The completion of this project will not only deepen our knowledge and understanding on the electrostatic properties of two-dimensional transition metal dichalcogenides, but also provide experimental guidance for the design and development of transition metal dichalcogenides based micro-nano devices.

单层或多层过渡金属二硫化物是一类具有类似石墨烯结构的新型二维层状材料，是现今纳米研究领域的一个新热点。二硫化钼、二硫化钨二维纳米材料因其独特的电子能带结构表现出优异的光电性质，将在下一代微纳电子和光电子器件等领域拥有广阔和重要的应用前景。然而过渡金属二硫化物纳米结构的可控制备仍然是一个很大的挑战，同时对于这类材料基本物理属性的研究还主要集中在电输运及光学性质方面，有关其表面电势、电荷分布等表面静电性质的研究还鲜有报道。本项目拟采用气相沉积法通过系统研究实现二硫化钼、二硫化钨二维纳米结构的可控制备。借助开尔文探针力显微镜深入研究过渡金属二硫化物不同纳米结构的表面静电性质，同时系统探讨不同湿度对其表面静电性质的影响规律，并阐明相应的物理机制。本项目的开展不但可以深化对过渡金属二硫化物静电性质的认识和理解，同时也将为基于二硫化物微纳器件的设计与发展提供一定的实验依据。

单层或少层过渡金属二硫化物MX2(M:Mo,W;X:S,Se)是一类具有类似石墨烯结构的新型二维层状材料,其在微纳光电器件领域具有广阔的应用前景。然而过渡金属二硫化物二维纳米结构的可控制备仍然是制约其应用与发展的一个很大的挑战，同时对于其表面静电性质研究的报道还非常少。在本项目的资助下，我们主要开展了以下几项工作：.1.利用气相沉积法实现了单层MoS2纳米片与纳米薄膜的可控制备，其中单晶尺寸可达200微米，纳米薄膜可达厘米尺寸。同时我们成功生长了具有不同褶皱结构的MoS2纳米薄膜，研究表明不同褶皱诱纳米结构导的应变可以对MoS2的表面静电性质进行有效的调控。.2.利用气相沉积法，实现了单层WSe2二维纳米片与纳米薄膜在不同基底的可控制备，其中单晶尺寸可达100微米，纳米薄膜可达厘米尺寸。同时我们对不同层数的WSe2表面静电性质进行了系统的研究，研究发现其表面电势随着层数的增加而增加，七层之后趋于块体值。.3.利用气相沉积法，实现了WS2不同二维纳米结构的可控制备并提出了相应的生长机制，同时对其微纳结构及其光电性能进行了系统的表征。