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In the process of preparing nanosilicon, the crystallization process is an important part to influence and improve the efficiency of nanosilicon luminescence. Thermal annealing, laser annealing, and electron beam irradiation are different ways of crystallizing the nanosilicon. Different photoluminescence (PL) spectra and structures of nanocrystalline silicon are observed for different treatment time of crystallization. The experimental results show that choosing an appropriate crystallization method and parameters is very important for preparing the nanosilicon crystalline structures. High luminous efficiency can be obtained by controlling the parameters properly in the processes of preparing silicon quantum dots (QDs) and quantum surface, especially. It is discovered experimentally that better nanosilicon crystalline structure such as nanosilicon QD structure, better PL luminescence, and the doped localized state luminescence of nanocrystalline silicon can be obtained when the crystallization time is about 20 min. According to the nanosilicon crystallization process under thermal annealing, laser annealing and electron beam irradiation, a physical model of the effect of crystallization time on the nanosilicon localized state luminescence is established in this paper, which can explain the effect of crystallization time on the localized state luminescence of the nanosilicon.

Photonic crystal not only can be used to inhibit the spontaneous emission and redistribute the energy into useful forms, but also can be designed to control and confine photons. Since the concept was introduced by John and Yablonovitch in 1987, there have been discussed the machinery of broadening the band bap and a quest for the optimal structure. Band structures of two-dimensional photonic crystals with different lattices and scatters of air hole of various shapes, orientations and sizes are investigated by the plane wave expansion method. The calculation results suggest that the variation of the photonic crystal band bap is attributed to the competition between symmetry and quantum confinement effects.