Application Of Rare Earth Element Yb In Ultraviolet Photodetector

UV photodetectors have been widely used in environmental monitoring,optical imaging,flame sensing,remote control,and lightwave communications.Traditional photomultiplier devices cannot meet people's daily needs due to their complex structure,large size,and high energy consumption.Broadband oxide semiconductors have attracted extensive attention in optoelectronic applications due to their good band gap width and photoelectric effect.At the same time,the broadband tight-band oxide only absorbs in the ultraviolet band,and has almost no absorption for visible light,which can effectively shield the influence of visible light,and is the preferred material for the preparation of ultraviolet detectors.At present,wide bandgap oxides such as TiO₂,Ga₂O₃,Sn O₂,Zn O,etc.,have important application value in the field of ultraviolet detection due to their excellent physical and chemical properties and convenient preparation methods.However,solar-blind semiconductors have low carrier lifetime,short machine lifetime,and many internal defects in the material.These problems lead to the fact that devices prepared from a single material cannot meet the requirements of high-performance UV detectors,so the preparation of high-performance UV detectors has become a hot topic.With the development of people's life,various fields have put forward higher requirements for the performance of ultraviolet photodetectors,and the development of devices with low dark current,fast response speed,and detection of solar blind spots has become the mainstream direction.Therefore,band engineering of materials or exploration of new materials has become a popular method in the field of UV detection technology.This dissertation focuses on the application of rare earth element Yb in ultraviolet photodetectors.The following research work is mainly carried out:At first,a Yb-doped TiO₂ UV photodetector with Au interdigitated electrodes was fabricated.Due to the limitation of the physical and chemical properties of TiO₂,the forbidden band width is only 3.2e V,and the absorption edge is close to 350 nm,which can only be used for visible blind detection.Therefore,Yb³⁺can be introduced into the lattice of TiO₂ by doping Yb.Ytterbium doping to form multi-metal oxides is beneficial to adjust the physical and chemical properties of materials from the perspective of energy band engineering,increase the forbidden band width of materials,and achieve more effective solar-blind detection of ultraviolet light.At 5 V bias voltage,the dark current of the detector is less than 1 n A.Under UV radiation,the device achieves a maximum switching rate of 3.64 x 10~3 with a recovery time from 1.4 s to 0.65 s when the doping concentration of Yb is 5%.Secondly,a Yb₂O₃ ultraviolet photodetector with Au interdigital electrodes was fabricated,which was the first time that Yb₂O₃ was applied to the field of ultraviolet detectors.Ytterbium oxide is a solar-blind semiconductor oxide with the same forbidden band width of 4.9e V as Ga₂O₃,so solar-blind detection of ultraviolet rays can be realized by making Yb₂O₃ ultraviolet photodetectors.In the experiment,the traditional sol-gel method and spin coating process were used,and the uniformly distributed nanoparticles were obtained on the quartz plate,with a diameter of about18 nm,and the Yb₂O₃ nano-film had good film-forming properties and no cracks on the surface.After that,a series of characterization and performance tests were carried out.The corresponding recovery times were all about 0.1s,the dark current reached below the nanoamp level,and the ultraviolet absorption wavelength was below280nm,realizing solar-blind detection of ultraviolet light.In this paper,ultraviolet photodetectors were fabricated by doping rare earth elements and applying new materials.The performance of existing devices under dark state and ultraviolet light irradiation is effectively improved,and the advantages in solar-blind detection are particularly prominent.This provides a new idea for the research on solar-blind UV photodetectors.