Size dependence of lifetime and absorption cross section of Si nanocrystals embedded in SiO2
Size dependence of lifetime and absorption cross section of Si nanocrystals embedded in SiO2
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DOI：
10.1063/1.1558894
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发表时间：
2003-03-01
影响因子：
4
通讯作者：
Cazzanelli, M
中科院分区：
文献类型：
--
作者：
Garcia, C;Garrido, B;Cazzanelli, M
研究了嵌入 SiO2 中的硅纳米晶体的光致发光寿命和光吸收截面与其平均尺寸和发射能量的函数关系。寿命范围从最小尺寸 (2.5 nm) 的 20 μs 到最大尺寸 (7 nm) 的 200 多μs。通过氢化作用钝化非辐射界面态可增加给定尺寸的寿命。与多孔硅相比，每个纳米晶体的横截面表现出随发射能量的非单调行为。事实上，尽管对于较大的纳米晶体，能隙上方的态密度会增加，但这种趋势可以通过振荡器强度的更大降低来补偿，从而使每个纳米晶体的吸收截面总体减小，以增加尺寸。 (C) 2003 年美国物理研究所。
Photoluminescence lifetimes and optical absorption cross sections of Si nanocrystals embedded in SiO2 have been studied as a function of their average size and emission energy. The lifetimes span from 20 mus for the smallest sizes (2.5 nm) to more than 200 mus for the largest ones (7 nm). The passivation of nonradiative interface states by hydrogenation increases the lifetime for a given size. In contrast with porous Si, the cross section per nanocrystal shows a nonmonotonic behavior with emission energy. In fact, although the density of states above the gap increases for larger nanocrystals, this trend is compensated by a stronger reduction of the oscillator strength, providing an overall reduction of the absorption cross section per nanocrystal for increasing size. (C) 2003 American Institute of Physics.