The Preparation Of Pyramid-like Texture ZnO:Al Thin Films And The Application As A Front Electrode In Amorphous Silicon Thin Solar Cells

ZnO:Al（ZAO） thin films are polycrystal with Wurzite hexagonal structure. And it is a N-type semiconductor thin film material. The conduction of ZnO:Al thin films is attributed to Al-doped and oxygen vacancies. ZnO:Al thin films possess the predominant electrical and optical properties, such as wide band of 3.34ev, high transparence in the visible spectrum and low resistance, which make them have wide applications in the fields of thin solar cell as the transparent electrodes.The pyramid-like texture ZnO:Al thin films were usually synthesized by MOCVD or acid-etching the as prepared RF magnetron sputtering films.But the expensive equipment cost and uncontronable respectively are two main disadvantages both the MOCVD and RF magnetron sputtered. In this paper, based on the preparation of pyramid-like texture ZnO:Al thin films and the application as a front electrode in amorphous silicon thin solar cells, the following researches were carried out:（1） Fabrication on a seed ZnO:Al layer coated on the quartz substrates by sol-gel methodUsing sol-gel technology, a seed ZnO:Al layer were fabricated by controlling the preparation parameters properly. The best technological conditions were obtained by optimizing, which are, sol concentration of 0.65mol/L; Al/Zn ratios of 4.0%; aging time of 48h; drying temperature at 150℃for 10 minutes; re-heat treatment at 260℃for 5 minutes; eight layers; annealing at 700℃.for 1hour.（2） Investigation on the texture ZnO:Al thin films prepared through a low-cost two-step processA ZnO:Al thin film was fabricated on the seed ZnO:Al layer by RF magnetron sputtered. By analyzing the structure, visible light transmittance and the resistivity of the thin films, the best technological conditions were obtained, which are the substrate temperature of 300℃, sputtering pressure of 1.0Pa, sputtering time of 2h and oxygen/argon ratio of 0/30. According to the measurement results of ZnO:Al films’resistivity and UV-Visible transmission spectra, the lower resistivity of 10^-3Ω·cm and optical transmission of higher than 80% were obtained for these ZnO:Al films.（3） The application of texture ZnO:Al thin films in a front electrode in amorphous silicon thin solar cellsTexture ZnO:Al thin films are used as the front electrode for amorphous silicon thin film solar cell. By analyzing the performance of the solar cells, it can be seen that the short circuit current density Jsc and open voltage Voc of the solar cells with ZnO:Al thin films as the front electrode are both better than those of the solar cells with SnO₂:F front electrode. So it can be a potential application of ZnO:Al thin film with trapping light in the front electrode in amorphous silicon solar cells.