Temperature dependence of localized exciton transitions in AlGaN ternary alloy epitaxial layers
Temperature dependence of localized exciton transitions in AlGaN ternary alloy epitaxial layers
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DOI：
10.1063/1.2975970
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发表时间：
2008-09
影响因子：
3.2
通讯作者：
Hideaki Murotani;Y. Yamada;T. Taguchi;A. Ishibashi;Y. Kawaguchi;T. Yokogawa
中科院分区：
文献类型：
--
作者：
Hideaki Murotani;Y. Yamada;T. Taguchi;A. Ishibashi;Y. Kawaguchi;T. Yokogawa
利用温度依赖性光致发光（PL）和时间分辨PL光谱研究了富Ga AlxGa 1-xN（x=0.019、0.038、0.057、0.077和0.092）三元合金外延层的光学性质。五个外延层中激子的发光强度表明了一个具有两个激活能的热猝灭过程。这两个猝灭活化能归因于激子的离域和激子的热解离。在外延层中也观察到PL峰能量的异常温度依赖性，这使得能够评估激子的局域化能量。局域化能随PL线宽的1.7次方增加，反映了局域激子态密度的展宽。此外，五个外延层的局域激子的发光衰减随着发射能量的降低而变长。这些结果表明激子的衰变不仅是由共振辐射引起的，而且是由电子的共振辐射引起的。
The optical properties of Ga-rich AlxGa1−xN (x=0.019, 0.038, 0.057, 0.077, and 0.092) ternary alloy epitaxial layers have been studied by means of temperature-dependent photoluminescence (PL) and time-resolved PL spectroscopy. The luminescence intensity of excitons in five epitaxial layers indicated a thermal quenching process with two activation energies. The two quenching activation energies were attributed to the delocalization of excitons and thermal dissociation of excitons. Anomalous temperature dependence of the PL peak energy was also observed in the epitaxial layers, which enabled the evaluation of the localization energy of the excitons. The localization energy increased as the 1.7th power of the PL linewidth, which reflected a broadening of the density of localized exciton states. In addition, the luminescence decay of the localized excitons for the five epitaxial layers became longer with decreasing emission energy. These observations suggest that the decay of excitons is caused not only by ra...