Preparation Of Low-dimensional ZnO Heterojunction Self-powered Ultraviolet Detector And Study On Its Response Performance

In recent years,ultraviolet（UV）detection technology has very important application value in the civilian and military area.Zn O has become one of the most promising UV photodetector materials owing to its direct and wide gap of 3.37e V,a large excitation binding energy of 60me V,low cost,simple preparation,high carrier mobility,good thermal stability and chemical stability.But it’s reported that Zn O based UV photodetectors suffer the problem of low responsivity,long response time and complex preparation method.In this paper,the performance of Zn O NRs based self-powered UV photodetector has been improved by heterojunction formation and surface passivation.The main achievements are as follows:（1）Zn O NRs were prepared on ITO conductive glass substrates by magnetron sputtering and hydrothermal methods,and their morphology,structure,and composition were tested and analyzed by SEM,XRD,and EDS.The effect of reactant concentration on the morphology of Zn O NRs was studied.As a result,when the Zn²⁺concentration was 0.025M,the growth quality of Zn O NRs was satisfactory,and there was a suitable gap between rods,which could reduce the recombination of carrier transport process and facilitates fast carrier transport along nanorods.（2）Zn O NRs/PEDOT:PSS heterojunction device was constructed.The research found that the device has a good photovoltaic effect under ultraviolet light,which can realize self-powered ultraviolet detection without external power.Under 0V bias and 365nm（0.8m W/cm²）UV light,the photocurrent of Zn O NRs/PEDOT:PSS heterojunction UV detector can reach250n A,the responsivity is 7.8m A/W.The rise time of this devices is 1s and its decay time is0.8s.（3）The sol-gel method was used to deposit Cu O layers on Zn O NRs,and the Zn O NRs/Cu O/PEDOT:PSS heterojunction UV detector was constructed.The thickness of the Cu O layer,light intensity,and bias voltage applied to the device were investigated.The study found that the Zn O NRs/Cu O/PEDOT:PSS heterojunction UV detector has good light response characteristics.Under 0V bias and 365nm（1m W/cm²）UV light irradiation,the devices can generate photocurrent～1.4μA,responsivity is 35m A/W.The rise time of this devices is 1.1s and its decay time is 1.5s.（4）The Ni O layer was deposited on Zn O NRs by magnetron sputtering and sol-gel methods,respectively.Zn O NRs/Ni O/PEDOT:PSS heterojunction UV detectors were constructed,and the factors affecting the light response performance of the device were explored.The study found that the Zn O NRs/Ni O/PEDOT:PSS heterojunction UV detector has excellent light response characteristics.Under 0V bias and 365nm（1m W/cm²）UV light irradiation,the photocurrent of the detector can reach～2.2μA,the responsivity is 55m A/W.