Time and Spatially Resolved Luminescence Spectroscopy of ZnO Nanostructures
Time and Spatially Resolved Luminescence Spectroscopy of ZnO Nanostructures
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DOI：
10.1007/978-81-322-1160-0_9
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
Hideaki Murotani;Y. Yamada;D. Nakamura;T. Okada
中科院分区：
文献类型：
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作者：
Hideaki Murotani;Y. Yamada;D. Nakamura;T. Okada
利用光致发光（PL）、时间分辨PL和空间分辨阴极发光（CL）光谱研究了未掺杂、P掺杂和Sb掺杂ZnO纳米结构（NS）的光学性质。分析了P掺杂和Sb掺杂ZnO纳米结构的PL谱的温度依赖性，并估算了P和Sb受体束缚激子的结合能分别为15和11 meV.这表明Sb杂质形成比ZnO中的P杂质浅的受主能级。由于双激子的辐射复合和激子的非弹性散射过程的PL线被清楚地观察到在未掺杂的ZnO NS，这使我们能够评估的激子和双激子的结合能为60和15毫电子伏，分别。这些值与本体ZnO中的值相同。从PL寿命和时间积分PL强度的温度依赖性估计的辐射和非辐射复合寿命。虽然未掺杂和P掺杂的ZnO纳米结构的辐射复合寿命几乎相等，但P掺杂的ZnO纳米结构的非辐射复合寿命比未掺杂的ZnO纳米结构的长。这表明P掺杂抑制了非辐射复合过程的热激活。CL图像显示，在P掺杂的ZnO纳米结构中，侧表面的强度远强于内部。另一方面，在Sb掺杂的ZnO NS中，CL强度几乎均匀地分布。这些观察结果表明，P杂质分布在NS的表面周围，Sb杂质几乎均匀地分布在NS上。
The optical properties of undoped, P-doped, and Sb-doped ZnO nanostructures (NSs) have been studied by means of photoluminescence (PL), time-resolved PL, and spatially resolved cathodoluminescence (CL) spectroscopy. The temperature dependence of the PL spectra of the P-doped and Sb-doped ZnO NSs was analyzed, and the binding energies of the P-acceptor- and the Sb-acceptor-bound excitons were estimated to be 15 and 11 meV, respectively. This indicated that the Sb impurities formed a shallower acceptor level than the P impurities in ZnO. PL lines due to the radiative recombination of biexcitons and the inelastic scattering processes of excitons were clearly observed in the undoped ZnO NSs, which enabled us to evaluate the binding energies of the excitons and biexcitons as 60 and 15 meV, respectively. These values were identical to the values in bulk ZnO. The radiative and nonradiative recombination lifetimes were estimated from the temperature dependence of the PL lifetime and the time-integrated PL intensity. Although the radiative recombination lifetimes for the undoped and P-doped ZnO NSs were almost equal, the nonradiative recombination lifetime for the P-doped ZnO NSs was longer than that for the undoped ZnO NSs. This suggested that the P doping suppressed the thermal activation of the nonradiative recombination processes. CL images revealed that the intensity of the side surface was much stronger than that of the interior in the P-doped ZnO NSs. On the other hand, the CL intensity was distributed almost uniformly in the Sb-doped ZnO NSs. These observations suggested that the P impurities were distributed around the surface of the NSs and that the Sb impurities were distributed almost uniformly over the NSs.