Effect of Temperature on the Structural and Optical Properties of Ga 2 O 3 Thin Films Grown on m-plane Sapphire Substrates by Low-Pressure MOCVD

In this paper, Ga 2 O 3 films were grown on m-sapphire substances at different temperatures of 600 °C, 700 °C and 800 °C by low pressure MOCVD. By changing the temperature, the crystal phase change of the Ga 2 O 3 thin films grown on the m-sapphire substrates were studied. The effects of temperature on structural characteristics, surface morphology and optical properties of the films were studied systematically. XRD results indicated that the mixture of α -phase and β -phase Ga 2 O 3 films were obtained on the m-sapphire substrates. As the temperature increased to 800 °C, the growth of α -Ga 2 O 3 was weakened. The degree of polycrystallization of β -Ga 2 O 3 decreased, and it gradually changed to preferential growth along the (−402) direction. With increasing of the temperature, the surface morphology of films was obviously changed. AFM measurement showed that the growth temperature has an important effect on the formation of Ga 2 O 3 grains. As the temperature increased, the grain size of the film gradually increased. The analysis results of Raman spectroscopy detected the Raman vibration modes of α -Ga 2 O 3 and β -Ga 2 O 3 . In addition, the photoluminescence properties of Ga 2 O 3 thin films have also been systematically studied. Compared with c-sapphire, Ga 2 O 3 thin films grown on m-sapphire substrates have more photoluminescence peaks, and the photoluminescence intensity increased with increasing temperature.