对分子束外延生长的 Ga NAs外延层进行了拉曼散射研究 ,观测到了由于导带中的 E+态所引起的共振散射和由此产生的布里渊区非Γ点声子的拉曼峰 .清晰地观测到了随氮含量增大 ,氮在 Ga As中的局域模振动演变为Ga NAs中的类 Ga N晶格声子带模 .通过样品在 850度快速热退火前后拉曼谱的对比 。
A set of a-SiOx :H (0.52 ＜x＜1.58) films are fabricated by plasma-enhanced-chemical-vapor-deposition (PECVD) method at the substrate temperature of 250℃. The microstructure andlocal bonding configurations of the films are investigated in detail using micro-Raman scattering,X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). It isfound that the films are structural inhomogeneous, with five phases of Si, Si2O:H, SiO:H, Si2O3:Hand SiO2 that coexist. The phase of Si is composed of nonhydrogenated amorphous silicon (a-Si)clusters that are spatially isolated. The average size of the clusters decreases with the increasingoxygen concentration x in the films. The results indicate that the structure of the present films canbe described by a multi-shell model, which suggests that a-Si cluster is surrounded in turn by thesubshells of Si2O:H, SiO:H, Si2O3:H, and SiO2.
