Origin of the Fine Structure of Ultraviolet and Visible Spectra of Silicon Nanocolloids in 2-Propanol

The origin of the fine structure of ultraviolet and visible absorption spectra of silicon nanocolloids in 2-propanol prepared in Ar atmosphere by a new sputtering method is studied. The fine structure is described by phonon-electron coupling in electron transition of silicon. On the basis of the structure model of Si-Si_4-nO_n(n = 0, 1,2,3,4), an energy relation has been proposed to explain the fine structure. The fine structure indicates strong multiple phonon absorption which depends on that how many oxygen atoms the silicon atom bonds to.