The Preparation Of AZO Thin Films And Their Applications In The Silicion-based Thin Film Solar Cells

Transparent conductive oxide films are one of important components of thin film solar cells. They have been widely utilized as front electrodes and back reflectors in thin film solar cells due to their good photoelectric performance. Transparent conducting films of high quality are the key to further improve the efficiency of solar cells.AZO (Aluminum doped zinc oxide) is a new kind of transparent conductive material which has been widely studied in recent years. It not only has excellent photoelectric properties but also has the advantages of low cost, rich in raw material and no pollution. Therefore, it is considered as one of the most promising materials for front electrodes and back reflectors in solar cells.In this thesis, the AZO films were deposited on glass substrate by RF magnetron sputtering method. The effects of the argon pressure, argon gas flow and the distance between the substrate and the target on the optical and electric properties of the thin films were studied, and these parameters were optimized. In order to reduce the resistivity, the AZO thin films were hydrogenated with the addition of H2into the argon atmosphere. When the thickness of the films is230nm, the square resistance is40.8Ω/□, which decreased more than6times compared to un-hydrogenated thin films, and the average transmittance in visible wavelength is higher than87%. The results indicate that hydrogen treatment of the AZO thin films can effectively improve the electric properties of the thin films.The AZO films which were optimized were utilized as the back reflectors for amorphous silicon germanium thin film solar cells. The results show that the AZO layers increased the QE greatly in the range from550to900nm, and increased Jsc from12.1mA/cm2to14.9mA/cm2. Meanwhile, the efficiency of solar cells increased by1%.Secondly, a graphene film was prepared on the AZO thin film. The AFM characterization shows that the graphene layer grown on AZO is rough. Compared with AZO films without graphene, the square resistance of the AZO with graphene increased, while its average transmittance changed little.At last, the AZO thin films were deposited on polyimide films by RF magnetron sputtering method. The thickness of the film is610nm and the square resistance of the film is16.7Ω/□. The average transmittance in visible wavelengths is more than89%.