摘要
采用射频磁控溅射的方法制备Zn掺杂TiO2薄膜,用XRD、SEM和UV-Vis分别表征TiO2薄膜的晶体结构、表面形貌及其紫外-可见光吸收谱。并用此材料制备Au/TiO2/Au结构MSM光电导型薄膜紫外光探测器,研究其光电特性。实验结果表明,Zn掺杂TiO2紫外探测器在250nm、5V偏压紫外光照下光电流约为500μA,其响应度为100A/W,平均暗电流约为0.5μA;由于ZnO/TiO2复合薄膜之间的费米能级不同而形成的内建电场作用,减少了产生的光生电子与空穴的复合,得到较强的光电流。且其光响应的上升迟豫时间约为22s,下降响应时间约为80s;响应时间较长是由于广泛分布于薄膜中的缺陷而造成的。结果表明Zn掺杂TiO2可作为一种良好的紫外探测材料。
The Zn-doped TiO2 thin films were prepared by RF magnetron sputtering, and their crystal structure, surface morphology and ultra-violet/visible absorption spectra were characterized by XRD, SEM and UV-Vis. Then, the photocurrent characteristics of the MSM-type photoconductive ultraviolet detector prepared with the films in Au/TiO2/Au system Were investigated. The results showed that the detector＇s photocurrent is 500μA when irradiated by UV light under 5V bias with 250nm wavelength and its responsivity is 100A/W, and the average dark current is 0.5μA. Zn-doped TiO2 UV detector has a higher photocurrent due to the built-in electric field formed by the different Fermi levels between TiO2 and ZnO, thus reducing the probability of combining the photoproduced electrons with voids so as to obtain higher photocurrent. The rising relaxation time for photoresponse of the TiO2 detector is about 22sec, while the lowering response time is about 80sec. The reason why the response time is long is the defects which spread over the film. The sensitivity and stability of the photoresponse indicated that the Zn-doped TiO2 thin films are proper to be a suitable material for UV detector.
出处
《真空》
CAS
北大核心
2009年第3期38-41,共4页
Vacuum
