Photoluminescence responses of Si nanocrystal to differing pumping conditions
Photoluminescence responses of Si nanocrystal to differing pumping conditions
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DOI：
10.1063/1.3601350
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发表时间：
2011-07
影响因子：
3.2
通讯作者：
Jiang Zhu;Xiang Wu;Miao Zhang;Yin Wang;X. Ning;You-yuan Zhao;Ming Lu
中科院分区：
文献类型：
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作者：
Jiang Zhu;Xiang Wu;Miao Zhang;Yin Wang;X. Ning;You-yuan Zhao;Ming Lu
在波长为 496 nm 的连续 Ar+ 激光束激发下，研究了多层 Si 纳米晶掺杂 SiO2/SiO2 样品（或 Si-nc:SiO2/SiO2）和单层 Si-nc:SiO2 样品的光致发光（PL）强度与泵浦功率密度的关系。对于多层样品，PL强度与泵浦功率从线性关系转变为超线性关系的泵浦功率密度阈值约为86 W cm−2，而在本工作的功率密度范围内具有相同过量Si含量的单层样品中没有发现这种转变。使用脉冲钛宝石激光器（波长= 400 nm），通过可变狭缝长度测量多层样品的净光增益系数，在泵浦通量为200 mJ cm−2时为114 cm−1，但单层样品仅发现光吸收。我们将结果归因于多层 Si-nc:SiO2/SiO2 相对较高的 PL 效率。
Under a CW Ar+ laser beam excitation with wavelength of 496 nm, the relationship of photoluminescence(PL) intensity versus pumping power density was investigated for both multilayered Si nanocrystaldoped SiO2/SiO2 sample (or Si-nc:SiO2/SiO2) and single-layered Si-nc:SiO2 one. The threshold of pump power density for the transition from linear to superlinear relation of PL intensity versus pump power was ∼ 86 W cm−2 for the multilayered sample, while such a transition was not found for the single-layered one that possessed the same excess Si content within the power density range of this work. Using a pulsed Ti:sapphire laser (wavelength = 400 nm), a net optical gain coefficient was measured by means of variable slit length for the multilayered sample, which was 114 cm−1 at the pump fluence of 200 mJ cm−2, but only optical absorption was found for the single-layered sample. We attributed our results to the relatively high PL efficiency of the multilayered Si-nc:SiO2/SiO2.