The Research Of The Properties Of Ga₂O₃ Thin Films And The Devices

Gallium oxide?Ga₂O₃?has five types of phase structures,and the?-Ga₂O₃ phase has excellent chemical and thermal stability.In addition,the forbidden band width of?-Ga₂O₃ is 4.9 eV,which can be just in the solar-blind band,and can be applied to the solar-blind UV detector.Now,wet-chemical and physical methods have been used to obtain?-Ga₂O₃ crystals with good crystal quality.The preparation methods are simple and safe.Although?-Ga₂O₃ has great application prospects in solar blind UV detectors,there are no clear experimental support for the types of defects existing in?-Ga₂O₃films and the detection of defect concentrations.In addition,the solar-blind detectors has been reported based on?-Ga₂O₃ thin film still have many disadvantages that the response is not high enough and the response time is not fast enough.Based on the analysis of the above,at first,this paper researches the internal defect of?-Ga₂O₃ thin films.Using pulsed laser deposition?PLD?technology,?-Ga₂O₃ thin films were grown on the c-sapphire.At last,based on the films preparing high-performance solar blind detectors.The main tasks are as follows:1)Using PLD technology to deposit?-Ga₂O₃ thin film on c-plane sapphire.the quality of?-Ga₂O₃ thin film can be controlled by the growth condition.Then,by the photoluminescence?PL?of the films grown at different pressures with the same temperature studying their luminous properties.and then,using x-ray photoelectron spectroscopy?XPS?to analyze the types and concentrations of defects present in the films.Finally,according to the results of PL and XPS analysis,the defect level transition spectrum of?-Ga₂O₃ thin film was obtained.It is concluded that there is defect-related luminescence radiation in the?-Ga₂O₃ film,3.3 eV of ultraviolet light comes from two self-captured vacancies related to the position of O?-s,and 3.0 eV of blue light comes from(V_Ga+V_O)^1-vacancy,the 2.7 eV of blue light comes from the(1^1-_{?6?vacancy at the Ga??octahedral?position.2}Using PLD method to prepare N-doped?-Ga₂O₃ films on c-plane sapphire.According to the best growth condition obtained from task 1,change the O₂ atmosphere to N₂O environment.Then,by adjusting the growth time,we get a single-layer pure?-Ga₂O₃ device,a single-layer Si:?-Ga₂O₃ device,a single-layer N:?-Ga₂O₃ device,and a double-layer N:?-Ga₂O₃/Si:?-Ga₂O₃ device.Pt?50 nm?was coated on different device surfaces by interdigital electrodes to obtain Schottky junction type solar blind photodetectors.The single-layer N:?-Ga₂O₃ device exhibits high response R=29.9 A/W,fast response time t _R=0.52 s,t_D=0.64 s,and the light-dark current ratio can reach 688(I_light/I_dark=688).While the double-layer N:?-Ga₂O₃/Si:?-Ga₂O₃ device shows the fastest photo-response speed and the largest light-dark current ratio.In addition,the double-layer device also exhibits excellent self-driving performance,providing a reference for the?-Ga₂O₃ self-powering device.