二维过渡金属二硫族化物(TMDCs)由于其独特的性能受到广泛关注。拥有适当的带隙和较大的比表面积、对可见光的快速响应、对气体的超敏感性，有望在场效应晶体管、 光开关、光探测器、气体探测等领域取得广泛应用。在这些二维材料中，WS2 的可控制备 一直是一个难题。本文利用化学气相沉积法，成功制备出边长约 200μm 的单层三角形 WS2 单晶。就 WS2 的可控制备进行了一系列的研究，总结出大致规律，并得到一套较好的参 数。制备了基于 WS2 的光电探测器，可用于检测波长<637nm 的光，其探测率达到 6.4× 1012Jones，对其施加一个 18V 的栅极电压后，对 20μW/cm2 光照的开关比达到 1000 以上。

关键词类石墨烯  二维材料  二硫化钨  气相化学沉积法  可控制备  光电探测器

毕 业 设 计 说 明 书 外 文 摘 要

Title  Chemical vapor deposition and photoelectronic performance of 2D tungsten disulfide films                 

Abstract：Two-dimensional (2D) transition metal dichalcogenides (TMDCs) have attracted wide attention due to their unique properties. Their sizable band gap, high surface-to-volume ratio, rapid response to visible light and hypersensitivity of gas, possess important potential applications in FETs, optical switches, photodetectors and gas sensors. However, as a specific member of 2D TMDCs materials, WS2 thin layers are less studied on their photoelectrical properties, and their controllable preparation has been a problem for a long time. In this paper, single layer triangular WS2 crystal with length of about 200μm was successfully grown by chemical vapor deposition. We had undertaken a series of studies on the controllable preparation of WS2, summed up the general law, and get a good set of parameters. Photodetectors based on WS2 films were prepared, which could be used in the detect of light with wavelength of less than 637nm, and exhibit an excellent detectivity (6.4×1012Jones). Normally, they don’t possess 

a good on/off ratio, but with a gate voltage of 18V, the ratio to light which power intensity is 20μW/cm2  could be more than 1000. 

Keywordsgraphene-like；two-dimensional materials；tungsten disulfide；CVD； controllable preparation；photodetector 

目次

1绪论 1

1.1引言 ·1

1.2  过渡金属二硫族化物1

1.2.1TMDCs 的晶体结构 1

1.2.2单层和少层 TMDCs 的性质 ·2

1.3TMDCs 的制备方法3

1.3.1微机械剥离法 ·3

1.3.2液相剥离法 ·3

1.3.3化学气相沉积法 ·4

1.4二维 WS2 薄膜的性质 4

1.5课题的提出5

2二维 WS2 薄膜的制备 ·6

2.1设备与材料6

2.1.1仪器与设备 ·6

2.1.2材料与试剂 ·7

2.2实验方法与过程 7

2.2.1材料及准备 ·7

2.2.2管式炉加热程序设置方法 ·8

2.2.3CVD 生长 WS2 薄膜 9

3光电探测器的制备11

3.1设备与材料 ·11

3.1.1仪器与设备 11

3.1.2材料与试剂 12

3.2实验方法与过程 ·12

3.2.1湿法转移 12

3.2.2显微干法转移 13

3.2.3后处理13

4结果与讨论14

4.1CVD 参数对 WS2 生长形貌的影响14

4.1.1衬底的温度对 WS2 形貌的影响14

4.1.2WO3 的温度对 WS2 形貌的影响15

4.1.3S 的温度对 WS2 形貌的影响15

4.1.4载气成分对 WS2 形貌的影响 

4.1.5小结 4.2WS2 的结构成分表征 ·

4.2.1光学显微镜和原子力显微镜(AFM)表征 ·