摘要
This paper reports on N-, mixed-, and Ga-polarity buffer layers are grown by molecular beam epitaxy （MBE） on sapphire （0001） substrates, with the GaN thicker films grown on the buffer layer with different polarity by hydride vapour epitaxy technique （HVPE）. The surface morphology, structural and optical properties of these HVPE-GaN epilayers are characterized by wet chemical etching, scanning electron microscope, x-ray diffraction, and photoluminescence spectrum respectively. It finds that the N-polarity film is unstable against the higher growth temperature and wet chemical etching, while that of GaN polarity one is stable. The results indicate that the crystalline quality of HVPE-GaN epilayers depends on the polarity of buffer layers.
This paper reports on N-, mixed-, and Ga-polarity buffer layers are grown by molecular beam epitaxy （MBE） on sapphire （0001） substrates, with the GaN thicker films grown on the buffer layer with different polarity by hydride vapour epitaxy technique （HVPE）. The surface morphology, structural and optical properties of these HVPE-GaN epilayers are characterized by wet chemical etching, scanning electron microscope, x-ray diffraction, and photoluminescence spectrum respectively. It finds that the N-polarity film is unstable against the higher growth temperature and wet chemical etching, while that of GaN polarity one is stable. The results indicate that the crystalline quality of HVPE-GaN epilayers depends on the polarity of buffer layers.
基金
Project supported by the National Natural Science Foundation of China （Grant No 10574130）.
