Researches On High Responsivity Photoconductors Based On Iron Pyrite Nanowires

FeS2(Pyrite), whose constituent elements content is very rich on the earth, is nontoxicity, environment friendly. As with suitable band gap and high absorption(α>5*105 for λ<700nm), FeS2(Pyrite) gain more attention in the photovoltaic application than their bulk counterpart. FeS2 can be prepared for solar cells and infrared photodetector. With the low cost, FeS2 is a potential candidate in the future PV material. Morever, FeS2 is applied in the clean resource field, which is consistent with the country’s appeal.This thesis demonstrates a new method of fabrication of FeS2 nanowire arrays via sulfurization of iron oxide nanotubes at relatively low temperatures. The precursor iron oxide is prepared by anodization. FeS2 nanowire arrays was fabricated into a prototype photoconductor. The photoconductor shows good I-V, I-t characteristics and high photoresponsitity.Firstly, the orderly iron oxide nanotube precursor film was prepared by anodization. The thesis expores how the anodizing parameter(DI water content, anodizing voltage and anodizing time) to control the morphology of anodic film. Through deep understanding of the mechanism, orderly iron oxide nanotubes film was prepared successfully.Secdondly, the iron oxide nanotubes film was sulfided into FeS2 nanowires. In the vacuum contition, iron oxide nanotubes film was thermally sulfided into FeS2 nanowires at the temperature of 400℃.The iron oxide can be transformed to FeS2 without Fe1-xS with the sulfurization time as short as two hours. The quite fast process is due to the high surface of the tubular structure. The extended sulfurization time does not lead obvious change in the morphology, crystal structure and absorption property of the Fe S2 nanowiresLastly, the FeS2 nanowires film was prepared into a simple prototype photocondunctor device. I-V and I-t properties of the device are measured with various voltage biasing the device. At the bias voltage of 2 V, the photoresponsitity is as high as 3A/W. With the increasing bias voltage, there is no obvious change in the photoresponsitity.