采用直流反应溅射法在P-Si(100)衬底上制备了ZnO薄膜,XRD测量表明ZnO为沿C轴高度取向的多晶薄膜,F-V特性曲线表明,ZnO/Si异质结具有明显的整流特性。研究了退火温度对异质结光电转换特性的影响,结果显示,合适的退火温度能显著增大异质结的开路电压和短路电流,进而增大异质结的光电转换效率,经400℃退火后异质结获得最佳的转换效率。当退火温度达到或超过500℃时,异质结的反向电流迅速增加,光生电压和光生电流大幅度减小。通过对ZnO薄膜结构和电学性质的测量和分析,推测异质结的光电转换特性改变主要受ZnO薄膜的电学性质影响。
ZnO films are deposited on the p type Si (100) substrates by DC reactive sputtering. I-V curves demonstrate that the ZnO/Si heterojunctions show obvious rectifying characteristics. The influence of annealing temperature on the photovoltaic effect is investigated. The results indicate that the appropriate annealing temperature can improve the open circuit voltage and short circuit current, accordingly, the photovohaic conversion efficiency increases markedly. The optimum annealing temperature is 400℃. However, when the annealing temperature is up to 500℃ and over it, the open circuit voltage and short circuit current decreased sharply, even it is close to zero. Based on the measurement and analysis of structure and electrical properties for ZnO thin films, it is suggested that the changes of photovoltatic effect of heterojunction due to these properties.