In掺杂ZnO薄膜的制备及其白光发射机理

Preparation and mechanism of In-doped ZnO emitting white-light

采用溶胶-凝胶法在Si衬底上制备了本征ZnO薄膜和In:(Zn+In)分别为5%,8%,10%的ZnO薄膜,对薄膜的晶相结构和光电性质进行了表征并在CIE-XYZ表色系统中计算了不同样品的色品坐标.结果表明:In掺入后ZnO薄膜的择优生长方向由(002)面变为(101)面且面间距变小,当In掺杂量为5%时,In原子完全替代Zn原子;薄膜的电阻率随In含量的增加出现先抑后扬的趋势;随着In的掺入光谱的紫外发射峰红移,并在670nm左右出现一个新的峰值;In:(Zn+In)为5%样品具有白光发射特性.从第一性原理出发计算了本征及In含量为5%的薄膜的能带结构,从附加能级的角度讨论了样品白光发射的产生机理.

Pure ZnO films and In/ZnO films are prepared by sol-gel process on Si substrates.The ratio of In/（Zn＋In） are 5%, 8% and 10% separately. Crystal phase structures and photoelectric properties of these films are characterized and these chromaticity coordinates of different samples are also calculated in a CIE-XYZ color system. The results show that preferred growth direction of ZnO film changes from （002） plane to （001） plane and interplanar distance becomes shorter. When doping amount of In is 5%, Zn atoms are replaced by In atoms. Resistivity of the film first decreases and the increases with the increase of the amount of In. Ultraviolet emission peak of spectrum has a redshift; a new peak emerges at 670nm with the increase of In. The sample of 5% emits white-light.The band structures of pure and 5% doping content of film are calculated based on first principles.The mechanism of emitting white-light is discussed from the view point of additional energy level.