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采用室温下微区Raman散射方法 ,观测到了GaInP2 的LO双模行为和禁戒的TO模 ,由于晶格有序导致晶体对称性从Td 降低为C3v,从而使禁戒的TO模变为Raman活性。在所有的样品中都观测到了由晶格无序激活的DALA模。在有序样品中 ,除观测到了二级Raman散射峰LO1+LO2 以外 ,还观测到了由超晶格效应所导致的FLA折叠模和LO模的分裂。对LO模峰谷比b/a的分析表明 ,随着晶格有序度的增加 ,b/a值减小。这是因为 :一方面主要是由于禁戒的TO模变为Raman活性所引起的 ,另一方面 ,还可能有LO1模和LO2 模分裂的贡献。在实验上 ,可以用b/a值或FLA的强度来表示样品的有序度。 相似文献
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利用MBE生长技术,成功地在不同晶向SrTiO3(100)(111)(110)衬底上生长了GaAs薄膜,利用显微Raman和荧光光谱(PL)对此进行了研究。实验结果表明,在不同晶向SrTiO3上生长的GaAs薄膜有不同的晶向和应力状态。荧光光谱(PL)研究表明在SrTiO3(100)(111)晶面上生长的GaAs薄膜的PL峰发生明显的蓝移。研究表明在SrTiO3(110)面上生长的GaAs薄膜和体单晶基本上一致,有更好的光学质量。 相似文献
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Raman spectroscopy has strong potential for providing non-invasion diagnosis of cancers. In this paper, micro-Raman spectroscopy is used to diagnose one most common liver cancer, hepatocellular carcinoma (HCC). The statistical analyzes, including t-test, principal component analysis (PCA), and linear discriminant analysis (LDA), are performed on the Raman spectra of malignant and normal hepatocytes. The t-test-LDA results show that the 786- and 1004-cm^-1 bands of the malignant and normal hepatocytes are significantly different, and PCA-LDA results show an overall accuracy of 100% for the Raman spectroscopic identification of normal and malignant hepatocytes in our experiment. 相似文献
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Micro-Raman spectroscopy is employed to identify the normal and malignant human stomach cells. For the cancer cell, the reduced intensity of the Raman peak at 1250 cm-1 indicates that the protein secondary structure transforms from β-sheet or disordered structures to α-helical, while the increased intensity of the symmetric PO2 stretching vibration mode at 1094 cm-1 shows the increased DNA content. The ratio of the intensity at 1315 cm-1 to that at 1340-1 reduces from 1.8 for the normal cell to 1.1 for the cancer cell in the course of canceration, and the ratio of the intensity at 1655 cm-1 to that at 1450cm-1 increases from 1.00 for the cancer cell to 1.26 for the normal cell which indicates that the canceration of stomach cell may induce saturation of the lipid chain. 相似文献