Control of Surface Morphology of Transparent Conductive ZnO Films by photo-MOCVD

为了控制氧化锌薄膜的表面形貌，研究了一些与沉积技术相关的方法。首先，以二乙基锌(DEZ)和水为反应气体，采用金属有机化学气相沉积(MOCVD)和光MOCVD方法成功地生长了氧化锌薄膜。以D2O和H2O为氧化剂对低阻氧化锌薄膜进行表面改性，制备了玻璃/氧化锌/三角掺杂p/Buffer/i/n/氧化锌/银/铝结构的非晶硅太阳电池。通过优化薄膜的颗粒尺寸和光电性能，在AM-1.5光照下获得了12.5%的高转换效率。为了提高氧化锌薄膜厚度和晶粒度的均匀性，采用了原子层沉积(ALD)技术。由于ALD的自限幅特性，薄膜具有良好的厚度均匀性，对于厚度仅为220 nm的未掺杂的氧化锌薄膜，电子迁移率高达30cm2/vs。通过对B_2H_6掺杂条件的优化，得到B掺杂的氧化锌薄膜的电阻率为6.4×10~(-4)&gt；OMEGAcm。此外，利用光致发光二极管技术还发现，在紫外光照射下生长的薄膜的电阻率比未经紫外光照射生长的薄膜低一个数量级。因此，这些氧化锌薄膜适合应用于太阳能电池。

To control the surface morphology of ZnO films, some approaches relating to deposition technique were studied. First, ZnO films have been successfully grown by metalorganic chemical vapor deposition (MOCVD) and photo-MOCVD using diethylzinc (DEZ) and H_2O as reactant gases. The surface morphology of low-resistivity ZnO films was modified by using D_2O along with H_2O as oxidants for DEZ.A-Si solar cells with a structure of glass/ZnO/delta-doped p/buffer/i/n/ZnO/Ag/AI have been fabricated. By optimizing the grain size of the films along with their electrical and optical properties, a high conversion efficiency of 12.5% was obtained under AM-1.5 illumination. In order to increase the uniformity of the film thickness and the grain size of ZnO films, the atomic layr deposition (ALD) technique was employed. The films had a good uniformity in thickness due to the self-limiting feature of ALD.A high electron mobility of 30cm^2/Vs was obtained for undoped ZnO films with the thickness of only 220nm. By optimizing the doping condition of B_2H_6, the resistivity of 6.4*10^<-4> OMEGAcm was achieved for B-doped ZnO film Furthermore, by using photo-ALD technique, it was found that the resistivity of the films grown with UV irradiation was one order of magnitude less than that grown without UV irradiation. Thus, these ZnO films are appropriate for application to solar cells.