Dominant free exciton emission in ZnO nanorods.
Dominant free exciton emission in ZnO nanorods.
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DOI：
10.1039/c2nr11773h
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发表时间：
2012-02
期刊：
影响因子：
6.7
通讯作者：
K. Wu;Haiping He;Yangfan Lu;Jingyun Huang;Z. Ye
中科院分区：
文献类型：
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作者：
K. Wu;Haiping He;Yangfan Lu;Jingyun Huang;Z. Ye
纳米结构的氧化锌被认为是一个很有前途的积木在纳米光电器件的设计。它通常在低温下显示出占主导地位的施主束缚激子（DX）发射。本研究采用金属有机物化学气相沉积法在a面蓝宝石（1120）衬底上生长了具有高结晶度和光学质量的ZnO纳米棒。光致发光光谱在低温（14 K）下观察到占主导地位的自由激子（FX）发射。这归因于高结晶质量的纳米棒引起的FX发射的增强和氢向外扩散引起的DX发射的抑制。通过光致发光光谱和二次离子质谱分析氢在纳米棒中的分布，后一个原因被认为是更重要的。建议在沉积期间缓慢冷却过程以获得更好的光学质量。这些结果可以促进我们对ZnO纳米结构光学性质的理解。
Nanostructured ZnO is considered to be a promising building block in the design of nanoscale optoelectronic devices. It usually shows dominant donor-bound exciton (DX) emission at low temperatures. In this study, ZnO nanorods with high crystallinity and optical quality were grown by metal-organic chemical vapor deposition on a-plane sapphire (1120) substrates. Dominant free exciton (FX) emission at a low temperature (14 K) was observed by photoluminescence spectroscopy. It was attributed to both the enhancement of the FX emission induced by the high crystalline quality of the nanorods and the suppression of the DX emission induced by hydrogen out-diffusion. The latter reason is believed to be more important from the analysis of the hydrogen distribution in the nanorods through photoluminescence spectroscopy and secondary ion mass spectrometry. A slow cooling process during the deposition is suggested to result in a better optical quality. These results can promote our understanding of the optical properties of ZnO nanostructures.