Research On Photodetectors Based On Titanium Dioxide Nanotube

As the space technology,information technology and the rapid development of electronic technology,ultraviolet detection technology has gradually become a kind of dual-use technology,widely used in scientific research,military,space exploration,environmental hygiene,and medicine application scenario.As the semiconductor materials research gradually thorough,the wide bandgap semiconductor materials for UV detection research provides a very promising direction.TiO2 is a kind of wide bandgap semiconductor materials,has advantages of simple preparation,high physical and chemical stability,has been wide researched and applied in photocatalysis,dye-sensitised solar cells and environmental pollutants purification and other fields.In this paper on the basis of TiO2 nanotube materials,we thoroughly studied the influence on the photoelectric performance of the detectors through materials morphology optimization and facet optimization.The main research results are as follows:(1)Through secondary anodic oxidation and heat annealing treatment method,this article prepared the highly ordered samples of TiO2 nanotube arrays.Based on the samples prepared under different heating speed in annealing process,we made UV photodetectors with Schottky structure,named as D1,D2 and D3.Device test results showed that the annealing temperature,the faster the speed,the worse the degree of order of TiO2 nanotube arrays and wall integrity,eventually leading to the decline of uv photodetectors in all kinds of photoelectric detection performance.The UV photodetector prepared based on the 2?/min annealing heat treatment,showing best in all kinds of photoelectric detection performance.(2)Based on first principle calculation,this article calculated the Partial Density of States(PDOS)and band structure of Anatase(001)facet and(101)facet,analyzing the differences of two facets electronic activity from the physical essence.(001)facet exposed TiO2 nanotube arrays samples were prepared by the method of anodic oxidation and water heating treatment.Based on the samples prepared under 130?,100? and70? water temperature condition,we made the UV photodetectors with Metal-Semiconductor-Metal(MSM)structure,named as D4,D5 and D6.Device test results showed that the higher the water temperature,the larger the ratio of Anatase(001)facet exposed,the greater the light current and probe light-to-dark ratio increased,and the better the photoelectric detection.The photodetector D4 which based on 130?water temperature had a very high light-to-dark ratio and spectral responsivity.Compared with TiO2 nanotubes UV detector without optimization,two types of UV photodetectors made in this article had a great improvement in all kinds of photoelectric detection performance,especially UV photodetector based on(001)facet exposed TiO2 nanotube arrays.The researches and applications of these devices have very significant prospect.