Observation of folded acoustic phonons in nanocrystalline silicon/amorphous sili

2019-10-12 05:10:47

silicon CM acoustic phonons folded

责任者: Wu, X.L.;Siu, G.G.;Stokes, M.J.;Tong, S.;Yan, F.;Liu, X.N.;Bao, X.M.;Jiang, S.S.;Zhang, X.K.;Feng, D. 单位: Lab. of Solid State Microstructures, Nanjing Univ., China 来源出处: Applied Physics Letters(Appl. Phys. Lett. (USA)),23 Sept. 1996,69(13):1855-7 摘要: We report in this letter the observation of folded acoustic phonons in hydrogenated nanocrystalline silicon/amorphous silicon multilayers with visible emission, which are prepared in a plasma enhanced chemical vapor deposition system. In the low-frequency range of 10-100 cm-1, the obtained Raman spectra clearly show some folded doublets from longitudinal acoustic phonons. Using the elastic continuum model, we calculated their frequencies and the obtained results were in agreement with the experimental ones. In addition, some broad folded doublets and additional peaks were clearly observed in the sample with thin nanocrystalline sublayers. We attributed them to the mixing of longitudinal and transverse acoustic phonons due to the layered structure. A confined acoustic mode was also proposed to be responsible for the strongly folded longitudinal acoustic phonon peak at 61 cm-1 关键词: amorphous semiconductors;elemental semiconductors;hydrogen;interface phonons;nanostructured materials;plasma CVD coatings;Raman spectra;semiconductor junctions;silicon;nanocrystalline silicon/amorphous silicon multilayers;folded acoustic phonons;PECVD;Raman spectra;longitudinal acoustic phonons;elastic continuum model;folded doublets;transverse acoustic phonons;confined acoustic mode;semiconductor;10 to 100 cm-1;61 cm-1;Si:H