(111)择优取向ZnS薄膜的制备及特性研究

Preparation and Characteristics of ZnS Thin Films with(111) Preferred Orientation

采用激光分子束外延技术在Al_2O_3衬底上成功外延生长了ZnS薄膜。用X射线衍射、扫描电子显微镜和光致发光谱表征了衬底温度对薄膜结构、形貌和光学特性的影响。结果表明所生长的ZnS薄膜为闪锌矿,具有(111)择优长向,随衬底温度的升高,X射线衍射峰的半高宽先减小后增大,在衬底温度为300℃时,半高宽最窄。薄膜结构致密,表面不平整度随衬底温度的升高而增大。薄膜的带隙随衬底温度的升高出现蓝移,可见光区域透射率最高达到98%,在360 nm激发波长下,观测到402 nm和468 nm两个发光带,衬底温度为300℃时,发光最强。

ZnS thin films were epitaxially grown on Al 2 O 3 substrates by laser molecular beam epitaxy.The structure,morphology and optical properties of ZnS thin films with different substrate temperatures were characterized by X-ray diffraction(XRD),scanning electron microscopy and photoluminescence spectra.The results of XRD show that the ZnS thin films with cubic structure reveal(111)high preferred orientation.With an increase of substrate temperature,full width at half maximum of the film decreases at first and then increases later,which is the narrowest with that deposited at 300℃.Band gap of the film has blue shift,and the highest transmittance in the visible region is 98%.Two photoluminescence peaks of 402 nm and 468 nm are observed under excitation wavelength of 360 nm,which reach maxunum of intensity with the film deposited at 300℃.