Structural and optical properties of textured ZnO:Al films on glass substrates prepared by in-line rf magnetron sputtering
Structural and optical properties of textured ZnO:Al films on glass substrates prepared by in-line rf magnetron sputtering
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DOI：
10.1016/j.solmat.2010.03.032
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发表时间：
2011
影响因子：
6.9
通讯作者：
J. Cho;Young-Jin Kim;J. Lee;Sanghyun Park;K. Yoon
中科院分区：
文献类型：
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作者：
J. Cho;Young-Jin Kim;J. Lee;Sanghyun Park;K. Yoon
采用同轴射频磁控溅射法在玻璃衬底上制备了具有优良光散射性能的织构ZnO：Al薄膜，并通过湿法刻蚀对薄膜表面形貌进行了修饰。精确控制薄膜的沉积参数和湿法刻蚀条件，以获得最佳的表面特征。在我们的实验条件下，所有的沉积薄膜都显示出强烈的[001]方向的择优取向。薄膜的微观结构受到工作压力的显著影响，薄膜的致密性随着工作压力的增加而降低，而衬底温度对薄膜微观结构的影响不太明显。在1.5mTorr和100°C下沉积的薄膜在可见光范围内具有4.25×10−4Ωcm的低电阻率和80%以上的高透光率。湿法腐蚀后，薄膜的表面形貌发生了很大的变化，这取决于初始薄膜的微观结构和薄膜的致密性。通过对薄膜表面形貌的控制，制得的ZnO：Al薄膜的雾度因子和角分辨分布较市售的SnO 2：F薄膜有明显的改善。将织构化的ZnO：Al和SnO 2：F薄膜用作a-Si：H/μc-Si：H串联结构硅薄膜太阳电池的衬底。与SnO 2：F薄膜太阳电池相比，μc-Si：H底电池的短路电流密度显著提高，这是由于高度织构化的ZnO：Al薄膜表面改善了600 nm以上长波长的光散射。
Textured ZnO:Al films with excellent light scattering properties as a front electrode of silicon thin film solar cells were prepared on glass substrates by an in-line rf magnetron sputtering, followed by a wet-etching process to modify the surface morphologies of the films. Deposition parameters and wet etching conditions of the films were controlled precisely to obtain the optimized surface features. All as-deposited films show a strong preferred orientation in the [001] direction under our experimental conditions. The microstructure of the films was significantly affected by working pressure and film compactness was reduced with increasing working pressure, while the effect of a substrate temperature on the microstructure is less pronounced. A low resistivity of 4.25×10−4Ωcm and high optical transmittance of above 80% in a visible range were obtained in the films deposited at 1.5mTorr and 100°C. After wet etching process, the surface morphologies of the films were changed dramatically depending on the microstructure and film compactness of the initial films. By controlling the surface feature, the haze factor and angular resolved distribution of the textured ZnO:Al films were improved remarkably when compared with commercial SnO2:F films. The textured ZnO:Al and SnO2:F films were applied as substrates for a silicon thin film solar cells with tandem structure of a-Si:H/μc-Si:H. Compared with the solar cells with the SnO2:F films, a significant enhancement in the short-circuit current density of the μc-Si:H bottom cell was achieved, which is due to the improved light scattering on the highly textured ZnO:Al film surfaces in the long wavelength above 600nm.