Optical properties of nanocrystalline silicon embedded in SiO_2  

作　　者：马智训 廖显伯 孔光临 褚君浩 

出　　处：《Science China Mathematics》1999年第9期995-1002,共8页中国科学：数学（英文版）

摘　　要：Nanocrystalline silicon embedded Si02 matrix has been formed by annealing the a-SiOx films fabricated by plasma enhanced chemical vapor deposition technique. Absorption and photoluminescence spectra of the films have been studied in conjunction with micro-Raman scattering spectra. It is found that absorption presents an exponential dependence of absorption coefficient to photon energy in the range of 1 .5-3.0 eV, and a sub-band appears in the range of 1.0-1.5 eV. The exponential absorption is due to the indirect band-to-band transition of electrons in silicon nanocrystallites, while the sub-band absorption is ascribed to transitions between surfaces and/or defect states of the silicon nanocrystallites. The existence of Stokes shift between absorption and photoluminescence suggests that the phonon-assist-ed luminescence would be enhanced due to the quantum confinement effects.Nanocrystalline silicon embedded SiO₂ matrix has been formed by annealing the a-SiO_x films fabricated by plasma enhanced chemical vapor deposition technique. Absorption and photoluminescence spectra of the films have been studied in conjunction with micro-Raman scattering spectra. It is found that absorption presents an exponential dependence of absorption coefficient to photon energy in the range of 1.5—3.0 eV, and a sub-band appears in the range of 1.0—1.5 eV. The exponential absorption is due to the indirect band-to-band transition of electrons in silicon nanocrystallites, while the sub-band absorption is ascribed to transitions between surfaces and/or defect states of the silicon nanocrystallites. The existence of Stokes shift between absorption and photoluminescence suggests that the phonon-assisted luminescence would be enhanced due to the quantum confinement effects.

关 键 词：NANOCRYSTALLINE silicon QUANTUM CONFINEMENT effect RAMAN SPECTRA ABSORPTION SPECTRA photolu-minescence. 

分 类 号：O472.3[理学—半导体物理]