The Research Of Growth And Optical Performance Of Rare Earth Doped Ga₂O₃Films

Rare earth luminescent material has drawn enormous attention from many researchers, mainly due to its innovative applications on light excitation device, solid laser, optical amplifier and optical waveguide (in near-infrared light communication system area), etc. Selection of host material directly affects the performance of rare earth luminescent materials, therefore, choose the appropriate host material is critical. Ga2O3has thermal and chemical stability, which is the largest forbidden band width semiconductor oxide known to the TCO materials, with the band gap about5eV, which makes it very suitable for finding or stimulating the ultraviolet, visible, near infrared spectrum, made it a good matrix of rare earth luminescent material.This article adopts the method of magnetron sputtering respectively prepared beta Ga2O3films and rare earth doped Ga2O3films; then analyzed their Crystal phase, optical and electronic properties respectively by means of X-ray diffraction (XRD), ultraviolet absorption spectrometer fluorescence spectrum electrical tester, and so on.Through system analysis we reached the main research contents and conclusions of this paper:(1) explored the basic growth parameters of beta Ga2O3thin film grown by magnetron sputtering deposition system, and discussed the influence of these parameters on the structural characteristics of thin film, then obtained the optimal growth parameters of beta Ga2O3is as follows: substrate temperature750℃, sputtering pressure1pa,sputtering power80w, sputtering time1.5h, thin films grow along a single orientation;(2) By placing moderate amount of pure rare earth oxides tablet on undoped Ga2O3ceramic target material, using RF magnetron sputtering technology prepared different concentrations of Ga2O3films doped separately with Er, Nd on the alpha Al2O3substrate, The influence of doping on its structure, optical and electric properties was also studied systematically, while with the increase of Er-doped concentration, the energy band gap Eg of film also increased; the light and dark current ratio of rare earth doped Ga2O3films under the254nm ultraviolet excitation can up to240, As thin film under365nm ultraviolet excitation has no photoelectric response, so we can know thin films prepared in our laboratory are response to specific wavelengths of light.(3) Transmission spectrum and reflectance spectrum have long been used to characterize gap semiconductor. Transmission spectrum can be measured very directly, but the influence of substrate absorption is often unavoidable. However, when using the reflectance spectrum measurement, the absorption of thin film, substrate absorption, and coherent interference will make the reflectance spectrum much more complicated. In this article,a method for determing optical constants of thin film is deduced by reflection spectrum theory;Related research work of the paper provides theoretical basis for the selection of rare earth doped substrate, at the same time it also enriches the theoretical knowledge of preparing beta Ga2O3films and rare earth doped beta Ga2O3films by magnetron sputtering method, making some efforts to further explore the rare earth doped Ga2O3films.