Study On Ultraviolet Detection Performance Based On Nanostructured Oxide

Ultraviolet(UV)detection,a new duel technology for military and civil field,has been widely applied in UV communication,pollution monitoring and biomedicine.Compared with traditional UV detectors,wide band-gap semiconductor based UV detectors have become the third generation of UV detectors due to their more rapid response,more precise measurement accuracy,higher visible light rejection ratio and free of filters.Among the different semiconductors,nanostructured oxide materials have unique physical and chemical properties different from bulk materials.The nanoscale size,huge specific surface area,high illumination sensitivity and anti-oxidation for the most of oxide make the nano-oxide received great attention in the UV detection filed.Zinc oxide(ZnO)and tin oxide(SnO2)are the representative direct wide band-gap semiconductor materials.The stable physical and chemical properties,large specific surface area and convenient preparation make the two oxide considerable materials for the UV detection.However,the numerous surface states and oxygen vacancies,could easily capture photogenerated carriers,which limit the detector performance.How to improve the performance of nanostructured ZnO and SnO2 based UV has been the research key point.Researchers usually conduct from these two aspects,material preparation and device construction.to optimize the device performance.In this paper,three parts of work are carried out as follow.1.The homogeneous morphology ZnO nanorods were synthesized by a simple solvothermal method.The nanorods were compounded with graphene to acquire good conductivity.The interface between the ZnO and graphene was optimized by silane coupling agent(APTES)to accelerate electron transfer.We used spin coating technique to fabricate UV detectors.The sensitivity of composite materials devices was 4 times of pure ZnO nanorods,and the responsivity and external quantum efficiency(EQE)were also greatly improved.In addition,the interface properties of composite and the mechanism of graphene on device performance improvement were studied.2.The nanocrystal self-assembled SnO2 nanospheres with large specific surface area were prepared by solvothermal method.The internal defects were eliminated by annealing process,and the crystal quality was improved.Then the composite of SnO2 nanospheres-graphene were prepared.The as-synthesized SnO2 nanospheres have a 3.86 eV band gap,which broaden the detection wavelength.It was found that Sn02 nanospheres were difficult to form homogeneous and condense film on the substrate.These disadvantages influenced the performance of SnO2 nanosphere-graphene based UV detectors.3.SnO2 nanoarrays with unique morphology were fabricated on the substrate by solvothermal method.In order to utilize the Localized Surface Plasmon Resonance(LSPR)effect of metals,gold(Au)nanoparticles were introduced to induce the growth of SnO2-Au nanoarrays.UV detectors were fabricated by plating aluminum(Al)electrodes on the nanoarrays.The as-fabricated UV detectors has high responsivity,high EQE and high detectivity under UV light with weak power density of 20 ?W/cm2 with 1 V external bias voltage.Besides,the effects of material morphology and gold nanoparticles on device performance improvement were deeply studied.