Preparation And Characterization Of UV-Transparent Conducting Ga₂O₃ Thin Films

With the development of semiconductor opto-electric technology, wide band-gap transparent conductive oxide thin films have been one of the researched focus in semiconductor materials fields. Gallium oxide (Ga₂O₃), as a kind of direct wide bandgap compound semiconductor material has been widely used as various gas sensors, ultraviolet detectors, liquid crystal display (LCD), transparent electrode materials in ultraviolet photoelectric devices and many other fields.In this paper, the widely used TCOs were reviewed;the properties and growth techniques of the Ga₂O₃ thin films and many applications in the modern technology were discussed. Using the special target holding models designed by myselves, the Ga₂O₃ thin films were prepared by direct current reactive magnetron sputtering and liquid gallium target. The crystalline and optical properties of the Ga₂O₃ thin film influenced by oxygen flux, substrate temperature and different oxide methods were studied. The properties of the films and the effects of growth parameters on quality of the Ga₂O₃ films were studied using X-ray diffraction, UV-Vis spectrophotometer, SEM techniques, infrared spectrophotometer, etc.Furthermore, the probably of the tin doped Ga₂O₃ films used as ultraviolet transparent electrodes was studied. Firstly, The result of the first principle calculation showed that Sn doped Ga₂O₃ films were n-type conductivity, the substituted Sn in Ga₂O₃ is donor. Based on the principle anticipation, the Ga_xSn_1-xO films were prepared using the double-targets magnetron sputtering. The different dopant concentrations were achieved by altering the sputtering time of tin to gallium.The results showed that the crystalline was better and the band-gap of films was reducing with the Sn increased. The electricity property measurement showed that the Ga_xSn_1-xO film was n-type conductivity and the resistivity of Ga_xSn_1-xO film was about 2.5 × 10³ Ω cm, which validated the results of the first principle calculation. Besides, the crystalline of films prepared by thermal oxidation were better than oxidation during reactive sputtering. The Ga₂O₃ films doped Sn was n-type conductivity , which is hopeful used in semiconductor ultraviolet photoelectric devices.