采用脉冲激光沉积方法以ZnS为靶材c面蓝宝石为衬底制备了一系列的ZnS薄膜,并采用四圆单晶衍射仪研究了薄膜的晶体结构及其与衬底的取向关系。首先研究了沉积温度对ZnS薄膜质量的影响,结果表明,所有制备的ZnS薄膜均为六方纤锌矿结构;在衬底温度为750℃时所制备的薄膜具有较好的晶体质量,并表现出与蓝宝石衬底明确的外延关系[ZnS(001)∥Al2O3(001)且ZnS(110)∥Al2O3(110)]。进一步研究了在750℃下加入不同厚度的ZnO缓冲层对于ZnS薄膜晶体质量的影响,结果表明在沉积ZnS薄膜前先沉积一层ZnO薄膜缓冲层可以进一步有效提高ZnS薄膜的晶体质量和面外取向性,其中在沉积时间为2min的ZnO缓冲层上制备的ZnS外延薄膜晶体质量最好,其(002)面摇摆曲线半高宽为1.35°。本文结论对于研究ZnS薄膜制备光电器件具有重要的意义。
A series of ZnS thin films were fabricated by pulsed laser deposition on c-sapphire using a ZnS target,and characterized by X-ray diffraction in terms of the crystal structure and orientation with respect to the sub-strate. Firstly, we have investigated the growth temperature effects on the quality of ZnS films in the tempera-ture range of 400-750 ℃. It was found that all ZnS thin films have a wurtzite structure, and the crystalline qual-ity of the ZnS films improves with increasing deposition temperature. The highest quality ZnS films were ob-tained at 750 ℃, which show epitaxial relationship with the substrate as ZnS(001)//Al2O3 (001) and ZnS(110)//Al2 O3 (110). Then we grew ZnS films with ZnO buffer layers deposited at different time (1, 2 and 3 rain) andfixed temperature of 750 ℃. The results suggest that applying a ZnO buffer layer can effectively improve thecrystal quality of ZnS films. In particular, the ZnS film grown with a 2rain-deposited ZnO buffer layer exhibitsa rocking curve half width of (002) plane as small as 1.35%. These results are of importance when consideringZnS films for making ZnS related optoelectronic devices.