Abstract: The authors perform combined temperature dependent macro-photoluminescence (PL) and confocal spatially resolved PL measurements to study the luminescence mechanism and the microcavity properties of one-dimensional CdS nanostructures (nanobelts and nanorods) grown by catalyst-assisted chemical vapor deposition. The dependence of the PL on the temperature (10-290 K) indicates clearly that the room temperature near band edge (NBE) emission mainly consists of excitonic emission and its phonon replicas. Both the end facets and the sidewalls of individual nanostructures may exhibit strong confinement on the NBE emission, leading to Fabry-Perot (FP) and whispering gallery (WG) cavities with pronounced nonlinear characteristics. The deep level defect emission forms strong cavity modes with equal spacings in WG cavities, but experiences large damping along the nanostructure axes in FP cavities. The results are helpful in understanding the mechanisms of the nanostructure optical microcavities, and support the exciton-polariton model of the exciton-related cavity modes.

Key words: one-dimensional CdS nanostructures, photoluminescence, optical micro-cavities

摘要： 运用低温变温宏观光致发光和共焦空间分辨光致发光光谱技术, 研究了由催化剂辅助化学气相沉积方法生长的一维CdS 纳米结构(纳米带和纳米棒)的发光机制及单个纳米结构光学微腔的性质。在 10~290K 之间, 光谱对温度的依赖关系清楚地显示了 CdS 纳米结构的室温近带边发光主要由自由激子发光及其声子伴线组成。 纳米结构的端面和侧壁均可对近带边发光表现出较强的束缚作用, 形成法布里-珀罗(FP)和回音壁 (WG)两种谐振腔,并表现出较明显的非线性特征。深能级的缺陷发光在 WG 微腔中形成较强的等间距腔模式, 而在FP 微腔中其在轴向上的传播则损耗较大。上述结果有助于理解两种纳米结构光学微腔的机制, 并支持了与激子相关的微腔模式的激子极化激元模型。

关键词: 一维CdS纳米结构, 光致发光, 光学微腔