二氧化钛/硅异质结光电导传感器的阻抗特性研究

The Study on Impedance Characteristics of Titanium Dioxide/Silicon Heterojunction Photoconductive Sensor

采用喷雾热解法在单晶硅(Si)上制备二氧化钛(TiO_(2))薄膜,以金属铟作为背电极构成TiO_(2)/Si异质结光电导传感器.采用X-射线衍射(XRD)、原子力显微镜(AFM)和拉曼光谱对样品的晶体微结构及表面形貌进行表征,通过紫外可见光谱研究TiO_(2)薄膜的光学吸收性能,在不同光照强度(5、10、15、20 mW·cm^(-2))下通过高精度数字电桥TH2828测试异质结的交流阻抗,并给出了等效电路并解释其光电导机制.

Titanium dioxide(TiO_(2)) thin film is prepared by spray pyrolysis on monocrystalline silicon(Si).TiO_(2)/Si heterojunction photoconductive sensor is formed by metal indium as back electrode on TiO_(2) thin film.The crystal microstructure and surface morphology of TiO_(2) film are characterized by X-ray diffraction(XRD),atomic force microscopy(AFM) and Raman spectrum.The optical absorption property of TiO_(2) film are studied by UV-vis spectroscopy.The AC impedance of the samples under different visible light intensities are tested by precision digital bridge TH2828.The equivalent circuit diagram of the test device is given to explained the mechanism of photoconductivity.