High-optical-gain UV Photodetector Based On ZnO Nanorods

The zinc oxide material has a wide bandgap(about 3.37 eV)and high exciton binding energy(60 me V)at room temperature,and can realize high-efficiency ultraviolet emission.It is an ideal ultraviolet luminescent material and has important applications in ultraviolet lasers,ultraviolet detectors.Among the various types of nanomaterials,one dimensional zinc oxide nanomaterials have becomed a hot topic in recent years because of their single direction electronic transport capacity,natural laser emission resonant cavity structure and larger specific surface area.Moreover,it has the advantages including the wide band gap of zinc oxide,the high binding energy of the exciton,the large electron mobility,the diversity of the zinc oxide nanomaterials'structures and the simple synthesis.Therefore,the research on one-dimensional zinc oxide nanomaterials is of great significance to the development of basic theory and production and application.In this paper,zinc oxide nanorods were investigated,and on the basis of which,the MSM-structured zinc oxide nanorods ultraviolet detectors were prepared.The main research contents and conclusions of this paper are as follows:(1)The zinc oxide nanorods were prepared by hydrothermal method.After the SEM and XRD were measured,the diameter and length of the prepared nanorods were 60-300 nm and 2?m,the nanorods exhibited characters of hexagonal wurtzite structure.UV-Vis absorption spectra was measured and it showed that the nanorods had strong absorption in the ultraviolet wavelength.(2)The zinc oxide nanorods were made into the MSM-structured ultraviolet detector,and the influence of the hydrothermal time and the time exposed to air(oxidized degree)on the performance of the device were explored,the optimum technical factors for device preparation was found.The responsivity of the final device was 0.445A/W at 10V and the detectivity 1.29×10¹² Jones at 2V.(3)The effect of surface modification of gold nanoparticles on device performance was studied.The optical gain of the new device was 100525 times,the responsivity was 0.663A/W at 10V,and the normalized detectivity was 1.84×10¹³ Jones at 2V,the response time was 44.24/29.4s.Among them,the optical gain and detection rate reached the highest values in the same type of device.The final device performance was significantly improved in all aspects.It was found that the improvement in performance came from the combination of surface plasmon effect and Schottky contact.