The Investigation Of Texture ZAO Thin Films Prepared By Two-step Process And Its Application As A Front Electrode In Amorphous Silicon Thin Solar Cells

ZAO thin films is polycrystal with Wurzite hexagonal structure and the N-type semiconductor thin films material. The electrical mechanism of ZAO thin films is attributed to doping with aluminum and oxygen vacancies which provide electronic. ZAO thin films possess the predominant electrical and optical properties such as wide optical bandgap 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 electrode.The pyramid-like texture ZAO thin films were usually synthesized by MOCVD or etching the as-prepared RF magnetron sputtering films, and the expensive equipment cost and uncontronable acid etching, respectively are two main disadvantages both the MOCVD and RF magnetron sputtered. In this paper, the pyramid-like texture ZAO thin films were prepared through a low-cost two-step process, firstly, a seed ZAO layer was coated on the quartz substrates by sol-gel method and subsequently a ZAO thin film was fabricated by RF magnetron sputtered.In this work, firstly, a seed ZAO layer was coated on the quartz substrates by sol-gel method. The best technological conditions were obtained by optimizing, which are, sol concentration of 0.80mol/L; aluminium doping concentration of 4.0at%; aging time of 5 days;drying temperature at 150℃; reheating treatment at 300℃; annealing at 800℃,for 1 hour; coating layers was eight. Subsequently, a ZAO thin film was fabricated by RF magnetron sputtered on the quartz substrates. Texture structure was not obtained through analyzing the film with microstructure, resistivity, surface appearance and ultraviolet visible light transmittance. Combining with the above two methods, we hypothesize boldly, use two-step process to prepare texture ZAO films: firstly, use the seed ZAO layer which was coated by sol-gel method as the self-support substrate and subsequently a ZAO thin film was fabricated by RF magnetron sputtered on the self-support substrate. Through the experimental analysis, good performance texture thin film was obtained. Tested by the four-point probe and Ultraviolet visible spectroscopy, the lower resistivisty of 10-3?·cm and optical transmission of higher than 85% were obtained for these ZAO films, and its surface morphology showed uniform texture structure arrangement.The texture structure ZAO conductive film which prepared by two-step process, was used as the front electrode in the amorphous silicon thin film solar cell, and the solar cell performance has comparable advantages as that of FTO conductive film. It was shown that ZAO thin film is a potential transparent conductive film which has light trapping property and can be used for the amorphous silicon thin film solar cell. It is hopeful to take the place of FTO thin film widely used in the amorphous silicon thin film solar cell.