The Fabrication Of ZnO Nanowires UV Photodetectors And The Research On Its Characteristics

ZnO is a hexagonal structure semiconductor material with a direct bandgap.Atroom temperature,the band gap is up to3.37ev and the exciton binding energyis60mev.In ZnO materials,ZnO nanowires have the remarkable physical propertiessuch as the large surface-to-volume ratios, vast-shape, simple preparationmethod,which make ZnO nanowires promising application potential in optoelectronicdevices.So far,the fabricated ZnO nanowires optoelectronic devices are usuallyvertical structure,but vertical structure have to fill the insulating material between thenanowires generally in order to avoid the short circuit.So this vertical structure donotshow the advantage of large surface-to-volume ration.Therefore,in order to solvethese problems, combines the laboratory conditions, this paper is focus on how tofabricate the plane ZnO nanowires UV detector and discuss the physical properties ofthe plane structure. The research is outlined as follows:1.zinc oxide (ZnO) nanowires metal-semiconductor-metal(MSM) ultravioletdetectors were fabricated on glass substrate by a single-step hydrothermal reactionand disccuss the properties of the devices.At first,ZnO seed layer were deposited onglass substrate by Magnetron Sputtering;then comb-shaped electrode were etched bylift-off lithography method. With the combined effect from a ZnO seed layer and aninactive layer for nanowires growth, ZnO nanowires could grow laterally and aligned between the comb-shaped electrodes. When the growth process is terminated, theintegration of ZnO nanowires into a function device can be achieved in themeantime.At last,we have discussed response time and responsivity.Fast responsetime is related with defects in nanowires.2. ZnO nanowires were arranged between electrodes of various shapes bydielectrophoresis method.We have found that ZnO nanowires were arranged along thedirection of the electric field lines. The amount of the ZnO nanowires betweenelectrodes were dominated by changing the concentration of nanowires.3. UV photoconductive detector of nanowire-based devices have beenfabricated by aligning ZnO nanowires into Au electrodes using dielectrophoresismethods. The Au nanoparticle (NP) decoration as an effective way to enhance themaximum responsivity and cut down the response time of the traditional region ZnOPD. The enhancement is caused by the enhanced space charge effect at the NWsurfaces, leading to a more pronounced electron-hole separation effect.