| Compared to the photomultiplier tube vacuum ultraviolet detector with large volume, high working voltage and the enhanced UV cathode silicon photodiode solid ultraviolet detector limited by the filter and light quantum efficiency, wide bandgap semiconductor UV detector has small volume, high quantum efficiency, wide dynamic working range, low noise, etc. ZnO with wurtzite structure is a direct wide-band gap n-type semiconductor material, it’s forbidden band width is 3.4 eV at room temperature(300 K), exciton binding energy as much as 60 me V, these unique properties make it suitable for making into a UV detector. In this paper, we prepared a good performance of ZnO nanowires, constructed a single ZnO nanowires photoelectric device, and through two methods to improve the performance of the zinc oxide nanowires ultraviolet detector.The first chapter, firstly introduces the related knowledge of nano materials and the research progress of one-dimensional nano materials, point out the one-dimensional nano materials ultraviolet detector and the research progress of one-dimensional nano materials photoelectric transport properties. This raises the purpose of our thesis research topic selection, and the main research content.The second chapter, we use the chemical vapor deposition method(CVD) grown zinc oxide nanowires in the [11-20] crystal plane of alumina substrate preparation successfully, and then the morphology and crystalline properties are characterized. Through representation we validate the nanowire growth mechanism is the gas- liquid- solid(V- L- S) growth mechanism. we both using dielectrophoresis method and electron beam etching method to build zno nanowires ultraviolet detection device with good performance.The third chapter, we studied the I-V curve and periodic on/off current changing with time curve characteristics under UV irradiation of the Au/Single ZnO NW /Au ultraviolet detector under the oxygen, nitrogen, vacuum environment. We found that the photocurrent of zinc oxide nanowires ultraviolet detector under ultraviolet light wavelength of 365 nm rise and reply the fastest in oxygen atmosphere. The photocurrent is much slower in nitrogen atmosphere and vacuum atmosphere. Then we discussed the physical mechanism of the phenomenon. We situ deposit a layer of Au nanoparticles on the zinc oxide nanowires ultraviolet detector and then studied the I-V curve and periodic on/off current changing with time curve characteristics. We found the response time of the Au deposited zinc oxide nanowires ultraviolet detector is 1/6, 1/3 and 2/3 of the device without Au NPs in the oxygen, nitrogen, vacuum atmosphere, respectively. While the switch ratio is the 100 times, 1.5 times, and 1 times,respectively. We think the good performance is mainly due to the Schottky barrier formed at the interface between gold nanoparticles and zinc oxide,which built electric field accelerates the composite effect of the electrons- hole, leading to the recovery time is accelerated. And big switch ratio in oxygen atmosphere is due to the gold particles makes itself for oxygen adsorption.The fourth chapter, we studied the charge injection effect on performance of zinc oxide nanowires ultraviolet detector. And then we found: when injected into positive charge, the recovery time of the device speed up, the switch ratio is bigger; when injected into negative charge, response time of the device slow down, the switch ratio is greatly reduced at the same time. We think the result is due to the electric field between injected charge and generated induced charge. If we inject positive charge, the direction of the electric field is from outside to inside. This electric field will promote the compound of photoproduction electrons and holes.Then the recovery time of the device speed up; If we inject negative charge, the direction of the electric field is from inside to outside. This electric field will prevent the compound of photoproduction electrons and holes.Then the recovery time of the device slow down. |
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