脉冲激光沉积GaN薄膜的结构和光学特性研究

Optical and Structural Properties of GaN Films Grown on Si Substrate by Excimer Pulsed Laser Deposition

采用准分子脉冲激光 ,在Si(111)衬底上生长了带有AlN缓冲层的GaN薄膜 ,利用X射线衍射 (XRD)、原子力显微镜 (AFM )和光致发光光谱 (PL)等测试手段研究了不同沉积温度所生长的GaN薄膜结构特征和光学性能 .研究表明 :沉积温度影响GaN薄膜结构和光学性能 ,黄带发射峰主要与晶体缺陷有关 在 4 0 0～ 70 0℃沉积范围内随着温度升高 。

GaN films have been grown on Si(111) substrates with a thin AlN buffer layer using a KrF excimer pulsed laser deposition(PLD) assisted by direct current discharge. The microstructure and optical properties of the GaN films were characterized by X-ray diffraction (XRD),atomic force microcopy (AFM) and photoluminescence (PL) spectroscopy. It is found that the structural and optical properties greatly depend on the substrate temperature during growth. The yellow band emission is mainly due to the defect caused by low growth temperature. The structural quality and optical properties of GaN films were improved by increasing the growth temperature from 400 ℃ to 700 ℃.