Study On The Heterojunction And Photoelectric Properties Of Graphene-titanium Dioxide Nanotubes

Ultraviolet?UV?photodetectors are widely used in UV warning system,combustion engineering,medical field and the defense system,as a new type of photoelectric detection technology has become one of the key research field of photoelectric detection.With semiconductor materials preparation technology and research progress,wide bandgap semiconductor materials with high temperature tolerance,only absorb ultraviolet light and suitable for use in the bad environment have developed as a focus in the current high-tech fields of scientific research and have been applied.TiO₂ has been widely applied in the fields of photoelectric detection,photocatalysis,dye-sensitized solar cells,water pollutant treatment,air purification and other related key technologies.Graphene consists of a layer of carbon atoms arranged tightly together by sp2 hybridization,forming a honeycombed structure.Due to its unique structure,it has excellent electrical and optical properties,which make it show broad potential in the fields of sensors,energy storage and display,semiconductor materials and biomedicine.In this paper,based on TiO₂ nanotube materials,we deeply studied material morphology and heterojunction optimization on the photoelectric detector photoelectric performance through the combination of high mobility of graphene into heterojunction.Firstly,TiO₂ nanotubes were prepared by anodic oxidation method.The morphology of different TiO₂ nanotubes was characterized by changing the anodic oxidation time and voltage,the morphology and photoelectric properties of heterojunction prepared by TiO₂ nanotubes with different lengths and diameters were studied.The test results show that the length of TiO₂ nanotubes increases with the increase of oxidation time,but decreases with the increase of oxidation time after reaching a certain oxidation time.It found that in a certain anodic oxidation voltage,the inner diameter of TiO₂ nanotubes increased linearly with the increase of voltage.Graphene and TiO₂ nanotube surface?the vertical growth direction along the tube?contacted,it formed the schottky junction in the contact area because of the the two different work function.Through photoelectric testing of graphene-TiO₂ nanotubes heterojunction made by TiO₂ nanotube with different anodic oxidation time,compared with the pure TiO₂ nanotube device,the photocurrent of graphene-TiO₂ nanotube device significantly increased,and the responsivity significantly improved,reaching 0.5A/W,and the specific detectivity add up to.3 3?10¹¹ cmHz^1/2W^-1.Further study found that the surface of TiO₂ nanotubes coated with a layer of TiO₂thin film,optimizing the contact of graphene with TiO₂ nanotubes and the contact between them becoming more smooth and more closely,can increase the photocurrent,further enhance the responsivity of the device and the specific detectivity.Responsivity is up to 72 A/W and specific detectivity is up to.1 2?10¹³ cmHz^1/2W^-1,greatly improved the overall performance of the device.In summary,the graphene-TiO₂ nanotubes heterojunction constructed by graphene and TiO₂ nanotubes prepared by anodic oxidation in this paper greatly improved the photoelectric performance of ultraviolet detectors.At the same time,TiO₂ thin film layer plated on TiO₂ nanotubes further improve the photoelectric performance of ultraviolet detectors,thus laying a foundation for the development and application of graphene-TiO₂ nanotubes heterojunction ultraviolet photodetectors.