Study Of High-performance Visible-near Infrared Light Photodetector

When the first man open his eyes, the natural photodetectors are working. After the first photodetector was successfully fabricated based on photoelectric effect, more and more kinds of photodetectors were made in our life to satisfy increasing demands, especially, the requirements of the military in infrared photodetectors. Although recenlty reported photodetectors show wide wavelength response in the range of ultraviolet to infrared, the researchers pay intensive attentions to improve the device performances. In this paper, two methods were introduced to improve visible-near infrared photodetector performance including new materials and surface plasmon resonance (SPR). The detailed results as follow:1. Topological insulators (TIs), which is insulators with metallic surfaces, generate a photocurrent with circularly polorized illuminating. Herein, Sb2Te3 thin films were succesfully synthesised by molecular beam epitaxy (MBE) method. Further characterization of the topological insulator film by using the angle resolved photoemission spectroscopy (ARPES) and X ray diffraction (XRD) indicated that the topological insulator is single crystall. A Sb2Te3-based photodetector was then fabricated via microelectric technique. Systematical photoresponse characteristization suggest that high photoconductive gain and responsivity up to 27.4 and 21.7 A W-1 were achieved, respectively.2. SPR is the charge-density oscillation that exist at the interface of two media with suitable size. We fristly synthesized the ZnTe nanowires (ZnTeNWs) by chemical vapor deposition (CVD), as well as ZnTeNWs with Au nano particles (AuNPs@ZnTeNWs). In order to investigagte SPR effect, the green light photoconductors detectors were constructed on ZnTeNWs and AuNPs@ZnTeNWs, respectively. The photoelectrical characterization show that most of merit of figure from AuNPs@ZnTeNWs are superior to the values of ZnTeNWs, such as an enhanced photocurrent near to 7 times. According to theroy simulation based on the finite element method (FEM), the enhancement is effectively attributed to the SPR.The results suggest that the above mentioned methods show a good potential in future photodetector research and applications.