Thermal effects on electron-phonon interaction in silicon nanostructures

摘要

Raman spectra from silicon nanostructures, recorded using excitation laserpower density of 1.0 kW/cm^2, is employed here to reveal the dominance ofthermal effects at temperatures higher than the room temperature. Roomtemperature Raman spectrum shows only phonon confinement and Fano effects.Raman spectra recorded at higher temperatures show increase in FWHM anddecrease in asymmetry ratio with respect to its room temperature counterpart.Experimental Raman scattering data are analyzed successfully using theoreticalRaman line-shape generated by incorporating the temperature dependence ofphonon dispersion relation. Experimental and theoretical temperature dependentRaman spectra are in good agreement. Although quantum confinement and Fanoeffects persists, heating effects start dominating at higher temperatures thanroom tempaerature.