The Reasearch On Well-aligned ZnO Nanorod Arrays UV Dector Fabrication And Its Property

In missile guidance, warning, ultraviolet communications, biomedical analysis, monitoring offshore oil fields, UV detector plays an important role. ZnO exciton bindingenergy is60meV at room temperature, band gap is3.37eV, ultraviolet laser emissioncan be realizes at room temperature.so,it’s an ideal material for UV detector. Base onlarge specific surface area, high electron-transport properity, ZnO nano-materials haspromising application in UV detector. Relative to the MSM structure andphotoconductive structure, p-n junctions and p-i-n structure UV detector has theadvantages of fast response, low voltage, high input impedance, high operatingfrequency. But,preparation of stable p-type ZnO is a worldwide problem. Currently thisstructure is constructed by using the n-type ZnO with other p-type material toachieve heterogeneous.We preparation of self-power UV detector and similar to p-njunction structure, but without p-type material and bias, with the advantages of quickresponse. Specific work as follows：(1)Magnetron sputtering technique is used to prepare the ZnO seed layer, highlyoriented nanorods is made by Hydrothermal Synthesis. With Al as the electrodematerial to prepared photoconductive ultraviolet detectors. The response of the deviceis1.73A/W, the response time is17s,the responsity is8times of ZnO films UVdetectors’. Changing the growth time of the nanorods array to control it’s Morphology.Responsity of the device increases with the growth time increas,the dark current of thedevice change little. But the response time of the device becomes longer.The nanorodsarray is annealled in air,O2atmosphere at500℃，the responsity of the device becomeslower, dark current increased, the response time of the device becomes longer.(2) We use a highly oriented ZnO nanorods arrays, redox electrolyte and Ptelectrode with catalytic properties, assemble into a self-power UV detector which is besimilar to Sandwich structure. Electron hole pairs separate in nanorods. Hole,electrolytes,and electronics form photochemical reaction cycle betweens emiconductorand Pt electrode. The UV dectector can detect375-395nm UV light without bias.Theresponsivity is0.013A/W, the response time is0.3s. The device has sthronganti-jamming capability to sunlight, Ion/Ioff=-257.7.We prepare devices with nanorods array with different morphologies,and found that the reponsity of the device that thethe nanorods growing60minutes gets to maximum,nonarods’ morphology hasalmost no effect on response time, and visible light current change little.(3) Nanorods array is modified by Ag coated and Ag nanoparticles.The size of Agparticle about10nm. nanorods modified by Ag coated reduces the responsity of thedevice. The nanoparticles can reduce the probability of electron-hole recombination,responsity is improved.But it has almost no effect on response time, and visible lightcurrent change little.