| ?-Ga2O3 is a wide direct bandgap semiconductor?4.5–4.9 eV?with excellent chemical stability and thermal stability,and has abroad development prospects in deep ultraviolet detection.The?-Ga2O3 ultraviolet detector can be fabricated based on?-Ga2O3 thin films and nanomaterials,but the?-Ga2O3 nanomaterials have larger surface-to-volume ratio and demonstrate superior sensitivity to surface processes than thin films and bulk materials,which has become a research hotspots at present.In this paper,?-Ga2O3 nanospheres with high yield,large area and uniform size were prepared by CVD method.Two kinds of different types of solar-blind UV detectors,Au/?-Ga2O3 nanospheres/Au and?-Ga2O3 nanospheres/p-Si heterojunction were fabricated based on?-Ga2O3 nanospheres,and their photoelectric properties were respectively studied.The major research achievements are listed below:?1??-Ga2O3 nanospheres with high yield,large area and uniform sizes were grown from gallium oxide powder and carbon powder by chemical vapor deposition method without any catalyst.The influence of growth temperature on the morphology,crystal quality and optical properties of the samples were investigated.The experimental results showed that with increasing growth temperature,the number of?-Ga2O3 nanospheres was obviously increased and the distribution was very dense.The diameter of nanospheres was about 200-700 nm.In addition,the full width at half maximum of the?-202?diffraction peak of the sample was decreased with increasing growth temperature.Combined with the SEM results,it was concluded that the optimum growth temperature of the?-Ga2O3 nanospheres in the experiment was 1200?.?2?The solar-blind UV detector based on Au/?-Ga2O3 nanospheres/Au structure has been fabricated by simple metal probe scratching method.Photoelectric tests showed that the ratio of light to dark current of the device was about 72,the responsivity was 6.7×10-3 A/W at a bias of 5 V,and the response rise and decay time of the device were 0.6 s and 0.83 s respectively.The results show that the device had a fast and sensitive detection performance for 254 nm ultraviolet light.In addition,the working mechanism of?-Ga2O3 nanospheres solar blind UV detector was also studied.?3?The?-Ga2O3 nanospheres/p-Si heterojunction solar-blind UV detector was fabricated based on the grown?-Ga2O3 nanospheres,and its photoelectric properties were studied.The results showed that the device had good rectifying characteristics and had obvious photoresponse to 254 nm ultraviolet light.The device showed self-powered characteristics at0 V bias.Photoelectric tests showed that the dark current was 0.13 nA,the photocurrent was131 nA,the ratio of light to dark current was about 1000,and the rise and decay time were about 1.46 s and 1.42 s respectively at 0 V bias. |
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