非晶Si/SiO_2超晶格的制备及其光谱研究

FABRICATION AND SPECTROSCOPIC STUDIES OF a-Si/SiO_2 SUPERLATTICES

用磁控溅射方法在玻璃基底上制备了非晶Si/SiO2 超晶格 .利用透射电子显微镜 (TEM)和X射线衍射技术对其结构进行了分析 ,结果表明 ,超晶格中Si层大部分区域为非晶相 ,局域微区呈现有序结构 ,其厚度由 1.8— 3.2nm变化 ,SiO2 层厚度为 4.0nm .并采用多种光谱测量技术 ,如吸收光谱、光致发光光谱和Raman光谱技术 ,对该结构的光学性质进行了系统研究 .结果表明 ,随纳米Si层厚度的减小 ,光学吸收边以及光致荧光峰发生明显蓝移 ,Ra man峰发生展宽 。

Amorphous Si/SiO 2 superlattices have been deposited on glass substrates using two target alternation magnetron sputtering technique. The samples are characterized using transmission electron microscope and low angle X ray reflectance techniques. The results indicate that most of the regions in Si layers consist of amorphous phase in the superlattices, while the regular structure appears in some local regions rarely. The thicknesses of Si layers are in a range from 1 8 to 3.2?nm and the thickness of SiO 2 layer is 4.0nm in all cases. The samples are systematically studied using absorption, photoluminescence (PL) and Raman spectroscopy techniques. The absorption edge positions and PL peaks shift towards shorter wavelengths while Raman spectra show broader peaks with decreasing Si layer thickness. The results are mainly attributed to the quantum confinement effects.