Photoluminescence quantum yields of amorphous and crystalline silicon nanoparticles
Photoluminescence quantum yields of amorphous and crystalline silicon nanoparticles
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DOI：
10.1103/physrevb.80.115407
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发表时间：
2009-09-01
影响因子：
3.7
通讯作者：
Kortshagen, Uwe
中科院分区：
文献类型：
--
作者：
Anthony, Rebecca;Kortshagen, Uwe
虽然纳米晶硅是一种有效的光发射体，但关于非晶硅纳米颗粒发射的报道很少，有时甚至是相互矛盾的。本文研究了用低温等离子体反应器合成的非晶硅和晶体硅纳米粒子的光学性质。通过调节输送到反应器的功率，将颗粒结构从无定形调节到结晶，而不会以显著的方式改变颗粒性质，例如纳米颗粒尺寸。两种不同类型的纳米粒子的表面钝化进行了研究：与有机配体的表面功能化的方案称为硅氢化和钝化与原生表面氧化物。我们观察到一个明确的趋势，光致发光量子产率的增加与主要是无定形样品的样品的结晶度的增加，表现出几乎没有发光。测量表明，非晶纳米颗粒的量子产率的上限为2%，而硅纳米晶体的量子产率通常超过40%。
While nanocrystalline silicon is known to be an efficient optical emitter, there have been few and sometimes contradictory reports of emission from amorphous silicon nanoparticles. This paper presents a study of the optical properties of amorphous and crystalline silicon nanoparticles synthesized by a nonthermal plasma reactor. By tuning the power delivered to the reactor, the particle structure was adjusted from amorphous to crystalline without otherwise changing the particle properties, such as nanoparticle size, in a significant manner. Two different kinds of surface passivation of nanoparticles are studied: the surface functionalization with organic ligands in a scheme known as hydrosilylation and the passivation with a native surface oxide. We observe a clear trend of the photoluminescence quantum yield increasing with the increasing degree of crystallinity of samples with largely amorphous samples, exhibiting almost no luminescence. Measurements suggest that the upper bound for the quantum yield of amorphous nanoparticles is 2%, while the quantum yield of silicon nanocrystals is routinely found to exceed 40%.