Enhanced photoluminescence caused by localized excitons observed in MgZnO alloy
Enhanced photoluminescence caused by localized excitons observed in MgZnO alloy
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DOI：
10.1063/1.3126703
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发表时间：
2009-05
影响因子：
3.2
通讯作者：
Hai Zhu;C. Shan;B. Li;Z. Zhang;J. Zhang;B. Yao;D. Shen;X. Fan
中科院分区：
文献类型：
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作者：
Hai Zhu;C. Shan;B. Li;Z. Zhang;J. Zhang;B. Yao;D. Shen;X. Fan
研究了MgZnO合金薄膜的光致发光随温度的变化，发现在一定温度范围内发光强度显著增加，然后随温度的升高而降低。MgZnO薄膜的拉曼谱中二阶纵向光学声子的增强表明，这种反常的增强是由MgZnO合金中的局域激子引起的.考虑到局域激子态的存在，提出了一个描述MgZnO薄膜中载流子输运过程的示意模型。研究结果表明，MgZnO合金中的局域激子可以显著提高发光效率，这是ZnO基材料在高效发光器件中应用的迫切需要。
Temperature-dependent photoluminescence of MgZnO alloy film has been studied, and it is found that the emission intensity increases significantly at a certain temperature range and then decreases when increasing temperature further. The anomalous increase is resulted from the localized excitons in MgZnO alloy, as revealed by the enhanced second-order longitudinal optical phonon in the Raman spectrum of the MgZnO film. A schematic model was suggested to depict the carrier transportation process in the MgZnO film considering the existence of localized exciton states. The results reported in this paper indicate that localized excitons in MgZnO alloy can result in greatly enhanced emission efficiency, which is eagerly wanted for the application of ZnO-based materials in high-efficiency light-emitting devices.