Research On Structure And Photoelectric Properties Of Rare-earth Doped ?-Ga₂O₃ Thin Films

Rare-earth ions have a unique electronic structure.This unique electronic structure makes rare earth luminescence generally have many advantages such as narrow emission line,wide band distribution range,high color purity,and almost no influence from the external environment.Communication,sensing and other fields have extremely wide applications and are recognized as a treasure trove of new materials.By doping the appropriate rare earth ions into a host material that is favorable for rare earth ion doping,it is expected to design novel functional materials with high fluorescence performance,detection and communication.The ?-Ga₂O₃ studied in this paper has a direct bandgap wide bandgap??4.9 eV?semiconductor material,which is easily excited by ultraviolet,visible and near-infrared spectra.It is an excellent matrix material that is favorable for rare earth luminescence.At the same time,the corresponding absorption wavelength of ?-Ga₂O₃ is 253 nm,which has a very high photoelectric response in the ultraviolet region and can be used to prepare high-performance solar-blind photodetectors.This article will also explore the preparation of a solar-blind UV photodetector based on rare-earth-doped ?-Ga₂O₃ thin film materials,and continue to optimize the device performance,to do some basic work for the development and application of high-performance detectors with broad application prospects.The main research work and results of this paper are as follows:?1??-Ga₂O₃ thin films and Pr-doped ?-Ga₂O₃ thin films were prepared on c-plane sapphire ?-Al2O3?0001?substrates by magnetron sputtering.The substrate temperature was 750 ? and the growth pressure was 1 Pa.With a sputtering power of 80 W and the sputtering time of 1.5 h,the prepared film grows preferentially along the?201?crystal plane.The effects of Pr ions doping on the structure and optical properties of?-Ga₂O₃ were studied systematically by X-ray diffraction?XRD?,UV-Vis spectroscopy?UV-Vis?and X-ray photoelectron spectroscopy?XPS?.The Pr ions have been successfully implanted into the ?-Ga₂O₃ lattice.When the Pr ion concentration increases,the energy band Eg of the film decreases.Under the excitation of a 255 nm Xenon lamp,the ?-Ga₂O₃:Pr film glows red and blue.Two emission spectra of Pr ion,one is the emission band centered on 490 nm,and the other is the emission band centered on 615 nm.The two excitation lights are the transition of the ion energy level from 1D2 to 3H4,and the 3P0/3P1/3P2 transition to the 3H4 excitation.?2??-Ga₂O₃ thin films and Ce-doped ?-Ga₂O₃ thin films were obtained by pulsed laser deposition on c-plane sapphire ?-Al2O3?0001?substrate.The substrate temperature was 750 ? and the pressure was 1 ×10-4 Pa.After the ?-Ga₂O₃ epitaxial film was deposited,the surface morphology,structure and optical properties,elemental composition,and valence and luminescence properties of the film were analyzed by the same characterization test method.The film was more sensitive to 254 nm UV light.Strong absorptive capacity;studied the control of Ce doping concentration to adjust the band gap and luminescence properties of the film,and analyzed the energy conversion model of rare earth doping,in order to further study the related devices based on the thin film material.?3?Based on ?-Ga₂O₃:Ce thin film,a metal-semiconductor-metal structure solar-blind UV photodetector device has been developed,which shows very obvious solar-blind UV optoelectronic characteristics.When the Ce ion doping amount is 0.7%,the photodetector sensitivity of the?-Ga₂O₃:Ce thin film can reach 3.2,and the response speed is also significantly higher than that of the non-doped ?-Ga₂O₃ thin film photodetector.The device integrates two important functions of light emission and detection.It can generate electrical signals and optical signals at the same time,providing a dual-mode detection function.