二维WS2薄膜的制备及光电特性

Preparation and Photoelectric Properties of Two-Dimensional WS2 Films

以硫化钨(WS2)水溶液为原料、氩气为携载气体、利用化学气相沉积(CVD)法在硅衬底上制备了二维WS2薄膜,并研究了其形貌、晶体结构、光吸收特性及光电特性等。发现利用该方法生长的WS2薄膜非常光滑均匀,并具有良好的结晶性。另外,发现WS2薄膜不仅在466 nm处有很强的蓝光发射,还在617和725 nm处有显著的红光发射,前者可能是由于量子尺寸效应引起的分立能级的发光,后者则分别对应WS2单层和多层的本征发射。最后,研究了WS2/Si异质结的光电效应和温度效应,发现随照射光功率或温度的增加,异质结的电流显著增大,说明WS2/Si异质结对光照和温度非常敏感,可用于制备太阳电池和光探测器等新型光电子器件。

Two-dimensional tungsten sulfide(WS2)films were prepared on silicon substrates by the chemical vapor deposition(CVD)method with WS2aqueous solution as the raw material and argon as the carrier gas.The morphology,crystal structure,light absorption characteristics and photoelectric characteristics of the WS2films were studied.It is found that the WS2films grown by the method are very smooth and uniform,and have good crystallinity.In addition,it is found that the WS2films have a strong blue emission at 466 nm,and have significant red emissions at 617 nm and 725 nm.The former may be due to the luminescence of the discrete energy level caused by the quantum size effect,while the latter corresponds to the intrinsic emissions of WS2 single layer and multilayer,respectively.Finally,the photoelectric effect and temperature effect of the WS2/Si heterojunction were studied.It is found that the current of the heterojunction increases significantly with the increase of the irradiation light power or temperature,indicating that WS2/Si heterojunction is very sensitive to the illumination and temperature and can be used to prepare solar cells,photodetectors and other new optoelectronic devices.