Influence of illumination of Raman spectra of porous silicons

2019-10-08 11:01:24

illumination line peak Raman phonons

责任者: Wu Xinglong;Yan Feng;Zhang Mingsheng;Feng Duan 单位: Nat. Lab. of Solid State Microstructures, Nanjing Univ.,, China 来源出处: Physics Letters A(Phys. Lett. A (Netherlands)),4 Sept. 1995,205(1):117-20 摘要: Raman spectroscopy of porous silicon has been performed as a function of the illumination time of incident light from an Ar+ laser using the 514.5 nm line. Two peaks with broad line shapes were obtained in the range 500-520 cm-1. The low frequency peak is sensitive to illumination. Its frequency shifts upward and its linewidth decreases with increasing the illumination time. The peak finally stays at 510 cm-1. Using a model of phonon confinement, we attribute the two peaks to the intrinsic feature peaks which arise from the contribution of both LO and TO phonons at phonon wavevector q≠0, whereas the upward shift of the Raman peak is ascribed to the disappearance of some small nanocrystallites induced by illumination 关键词: elemental semiconductors;phonons;porous materials;Raman spectra;silicon;spectral line breadth;spectral line shift;Raman spectra;porous silicon;illumination time dependence;laser radiation;broad line shape;frequency shift;phonon confinement;LO phonons;TO phonons;Raman peak;500 to 520 cm-1;Si