A Study Of The Doping And Photosensitivity Properties Of β-Ga₂O₃Thin Films Prepared By L-MBE

With the development of science and technology, a transparent conductive oxide films indomains such as flat panel displays, light emitting diode applications, solar transparent electrodeattracted more and more people’s attention. Gallium oxide as an band-gap semiconductormaterial with its high band gap, excellent deep ultraviolet transparent is becoming a hot topicafter ZnO.In this paper, a method of laser molecular beam epitaxy was used to prepared the β-Ga2O3thin films on single crystal Al2O3(0001) substrates. For studying the doping problem of β-Ga2O3,we discussed it from both theoretical and experimental aspects. To research the photosensitiveproperties of the films, we prepared ultraviolet photodetector which has a MSM structure andtested its performance. The main results achieved in this dissertation can be summarized asfollowing:1. We got the optimal parameters of preparing high quality oriented thin films, through aseries of experiments. The optimized parameters are as follows: oxygen pressure10-2Pa,substrate temperature750℃, the target-substrate distance (the distance between target materialsand the substrate)4.5cm, and then annealed at800℃.2. We characterized the β-Ga2O3thin films. It contained: used RHEED to analyze thesurface morphology of the film real time and qualitative, used X-ray diffraction to analyze theinternal structure, by measuring the fluorescence emission and ultraviolet-visible absorptionspectrum to analyze the optical properties.3. Discussed the doping problem of β-Ga2O3from theoretical and experimental two aspects.Analyzed the band structure and density of states of Ni doped β-Ga2O3.On the other hand, weprepared Ni doped β-Ga2O3films with different doping ratio and characterized their changes insurface morphology, band-gap, and optical properties.At last, we used Raman scattering toanalyze the vibration of doped films.4. Blind Ultraviolet detector prototype device was successfully prepared, and got a goodblind photosensitive effect. We calculated its light responsivity and measured its risen and attenuated relaxation time. Discussed the disadvantage of the device, and wished to rise itsperformance.