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Hole-net structure silicon is fabricated by laser
irradiation and annealing, on which a photoluminescence (PL) band in a
the region of 650--750~nm is pinned and its intensity increases
obviously after oxidation. It is found that the PL intensity changes
with both laser irradiation time and annealing time. Calculations
show that some localized states appear in the band gap of the
smaller nanocrystal when Si=O bonds or Si--O--Si bonds are
passivated on the surface. It is discovered that the density and the
number of Si=O bonds or Si--O--Si bonds related to both the
irradiation time and the annealing time obviously affect the
generation of the localized gap states of hole-net silicon, by which
the production of stimulated emission through controlling oxidation
time can be explained. 相似文献
2.
纳秒脉冲激光在氮气、氧气和空气等不同氛围中加工出的硅量子点都有光致荧光(PL)的发光增强效应,并且在700 nm波长附近观察到了受激辐射.在不同氛围下生成的样品有几乎相同的PL光谱分布,其原因是不同氛围下加工出的样品带隙中有相同的电子态分布.计算结果显示:当硅量子点表面被氮或氧钝化后,在带隙中能够形成几乎相同的局域电子态,这种局域电子态可以俘获来自导带的电子,从而形成亚稳态,这是PL发光增强乃至产生受激辐射的关键因素.
关键词:
硅量子点
PL光谱
发光增强
电子局域态 相似文献
3.
经过激光辐照和高温退火加工能够生成多孔硅样品,在650—780 nm处检测到很强的光致荧光(PL)峰,并且有明显的钉扎和增强效应.实验表明,这种PL发光的强度与样品受辐照和退火的时间短密切相关.通过第一性原理模拟计算发现,样品表面用SiO 双键和Si—O—Si桥键钝化,能隙中会出现电子局域态.激光辐照和高温退火的时间长短决定了样品表面SiO双键和Si—O—Si桥键的密度,而该密度正是影响多孔硅量子点中电子局域态生成的关键.
关键词:
多孔硅量子点
硅氧钝化键
电子局域态 相似文献
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