Study On Fabrication And Performance Of Al-Sn Doped ZnO Thin Films And AZO/p-Si Heterojunctions

ZnO is a II-VI group compound semiconductor material with a direct wide band-gap. The dopedZnO thin film not only possesses metal-like conductivity, but also performs high transmittance ofvisible light. Because ZnO thin films are low-cost, high stability in hydrogen plasma environment andeasily to be deposited at low-temperature, they have great potential in the thin-film solar cells, UVdetectors, light-emitting devices, thin film transistors, flat panel displays and other fields. It is themost promising alternative to ITO thin film materials.In this thesis, Sn doped ZnO（TZO） thin films, Al&Sn co-doped ZnO（ATZO） thin films, andAZO/p-Si heterojunctions were prepared by RF magnetron sputtering. The influences of Sn sputteringpower, substrate temperature, growth time on the TZO and ATZO thin films properties were studied.The impact of annealing on AZO/p-Si heterojunctions rectifying behavior and photovoltaic effectwere investigated. The main results were obtained as follows:1. TZO thin films: Firstly, TZO film reached the minimum resistivity of6.99×10^-2cm when theSn sputtering power was20W. The average transmittance was77.19%between400nm and900nmband, had smallest corrosion current density of2.59×10^-8A/cm2and maximum polarization resistanceof1.20×106. Secondly, the influence of substrate temperature was investigated. The crystallinequality of TZO films became better as the substrate temperature increased from30℃to160℃, andthe conductivity was enhanced by1.43times. At Last, we studied the effect of growth time. Thecrystalline quality of TZO films became better along with the growth time increasing. The averagelight transmittance was up to80.35%and the resistivity was down to5.04×10^-2cm.2. ATZO thin films: Firstly, ATZO film reached the minimum resistivity of1.49×10^-3cm whenthe Sn sputtering power was5W. The average transmittance was88.77%between400nm and900nmband. ATZO film had the smallest corrosion current density of1.29×10^-8A/cm2and maximumpolarization resistance of1.40×106when the Sn sputtering power was10W. Secondly, the influenceof the substrate temperature was investigated. The crystalline quality of ATZO films became better asthe substrate temperature increased from30℃to160℃, and the conductivity was enhanced by2.55times. At last, we studied the growth time effect on ATZO films performance. The crystalline qualityof ATZO films became better along with the growth time increasing. The average light transmittancewas up to90.90%and the resistivity was down to6.93×10-4cm.3. AZO/p-Si heterojunctions: The rectification and photovoltaic properties of the as-prepared and annealed AZO/p-Si heterojunctions were studied. The results showed that the anneal process couldimprove the rectifying behavior and photovoltaic effect of the heterojunction. After the heterojunctionwas annealed, the rectification ratio was increased by4.71times compared to the as-deposited one.The ideality factor was aboat more close to2and the photoelectric conversion efficiency wasincreased by0.81%.