Synthesis of monoclinic structure gallium oxide film on sapphire substrate by magnetron sputtering

摘要

Gallium oxide(Ga_2O_3) films were deposited on singlecrystalline sapphire(0001) substrate by radio frequency(RF) magnetron sputtering technique in the temperature range of 300—500 °C. The microstructure of the β-Ga_2O_3 films were investigated in detail using X-ray diffractometer(XRD) and scanning electron microscope(SEM). The results show that the film prepared at 500 °C exhibits the best crystallinity with a monoclinic structure(β-Ga_2O_3). Structure analysis reveals a clear out-of-plane orientation of β-Ga_2O_3(201) || Al_2O_3(0001). The average transmittance of these films in the visible wavelength range exceeds 90%, and the optical band gap of the films varies from 4.68 eV to 4.94 eV which were measured by an ultraviolet-visible-near infrared(UV-vis-NIR) spectrophotometer. Therefore, it is hopeful that the β-Ga_2O_3 film can be used in the UV optoelectronic devices.