摘要
本文报道了利用 MOCVD方法 ,在 Ga As衬底 ( 0 0 1 )面制备的立方 Ga N薄膜的光学性质 .利用光致发光 ( PL )光谱的半高宽确定制备的样品具有不同的晶体质量 .利用喇曼散射( RS)光谱研究了立方 Ga N薄膜中的光学声子模式 .横向 ( TO)和纵向 ( LO)声子在立方 Ga N中的散射峰分别位于 552 cm- 1和 739cm- 1.另外还观察到来自界面无序层的 TOB和 LOB.根据喇曼频移和选择定则可识别 Ga N中的相组成 .其来自六方相 Ga N的 E2 声子模 ,可作为识别立方 Ga N中六方相的标志 .随着退火温度的升高 ,样品中的界面层的效应减弱 。
We report the optical characterization of the cubic GaN film grown on GaAs (001) by MOCVD. The FWHMs of the PL spectra show that the c\|GaN samples have different crystal quality. Raman spectra are used to study the optical phonon modes in the c\|GaN epitaxy layer. TO and LO phonon peaks are found at 552cm -1 and 739cm -1 , respectively. Besides these emissions, we also observe the TO B and LO B phonons attributed to the boundary layer in sample C. The E 2 phonon from hexagonal phase can be used to identify the hexagonal phase. Annealed at higher temperature, the boundary layer effect decreases while the quantity of hexagonal phase increases in sample C.
基金
国家"8 63"高技术计划资助项目
关键词
砷化镓
MOCVD法
氮化镓
外延生长
Metallorganic chemical vapor deposition
Semiconducting films
