Study On The Thermosensitive And Photoconductive Properties Of Li-and Mg-doped ZnO Micro/nano-materials

ZnO is an important direct wide bandgap semiconductor with a bandgap of 3.37 eV,a large exciton binding energy of 60 meV,and ZnO has various and feasible ways to fabricate that makes it an alternative materials of GaN which is more complicated to synthesis.ZnO is appreciated as a promising materials in short-wavelength photoelectric device especially ultraviolet photoelectric detector.At present,research on the wide spectra response and thermosensitivity of ZnO isn’t comprehensive.In order to obtain a photoresponse not limited to ultraviolet range and a high performance of thermosensitivity,in this paper,the properties of ZnO was modified by doping with Li and Mg respectively.The doped micro/nano-materials were fabricated via an economic and feasible Low-Temperature Combustion method and the thermosensitive and photoelectric properties were researched in details.The main results are listed as follows:1.The thermosensitive properties of Li-doped and Mg-doped ZnO micro/nanomaterials were investigated respectively.Samples both showed a negative temperature coefficient and stable,outstanding thermosensitive properties were observed in the temperature range from room temperature to 250 ℃,enhancement in thermoelectric properties was achieved by doping through the comparison of doped and pure ZnO micro/nano-materials.2.The photoconductive properties of Li-doped ZnO micro/nano-materials annealed at 600 ℃ were investigated,ZnO/Ag contact was formed an Ohimc contact,and persistent photoconductivity was observed in experiment.The device showed a high selective response in ultraviolet range and produced a strong photo response,the ratio of photo current and dark current is up to two orders.The micro/nano-materials annealed at 1000 ℃ obtained a higher dark current and led to the low switch ratio,but the spectra response was broadened.3.Wide spectra response of Mg-doped ZnO micro/nano-materials were investigated in details.A blue shift of near bandgap emission was observed,and the device showed stable and strong photo response in the whole spectra range of 200-900 nm.Besides,the stability and repeatability of photo response under different wavelength are good.