Temperature-dependent Raman scattering studies in nanocrystalline silicon and fi

2019-11-04 23:47:11

temperature size silicon dependent phonon

责任者: Mishra, P.;Jain, K.P. 单位: Dept. of Phys., Indian Inst. of Technol., Delhi, India 来源出处: Physical Review B (Condensed Matter)(Phys. Rev. B, Condens. Matter (USA)),2000/12/01,62(22):14790-5 摘要: A comparative study of the temperature-dependent Raman scattering of nanocrystalline and bulk silicon is presented. The nanocrystalline silicon samples were made by a cw laser annealing process, and the characteristic dimensions were determined with a phenomenological phonon confinement model. Experimental results indicate a higher degree of anharmonicity in nanocrystals compared to that in the bulk. The anharmonic constants are found to be highly size dependent and increase greatly with decreasing dimensions. The phonon lifetimes have two contributions, one temperature dependent and the other temperature independent, both decreasing rapidly with decreasing nanocrystal size. The temperature-dependent term τ0 is important for larger nanocrystals, while the temperature-independent term τ1 becomes dominant for nanocrystals of sizes less than 4 nm 关键词: anharmonic lattice modes;elemental semiconductors;laser beam annealing;nanostructured materials;phonon spectra;Raman spectra;silicon;temperature-dependent Raman scattering studies;nanocrystalline silicon;finite-size effects;bulk silicon;CW laser annealing process;characteristic dimensions;phenomenological phonon confinement model;anharmonicity;phonon lifetimes;nanocrystal size;Si