Dynamics of anomalous optical transitions in Al x Ga 1 − x N alloys
Dynamics of anomalous optical transitions in Al x Ga 1 − x N alloys
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DOI：
10.1103/physrevb.61.7203
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发表时间：
2000-03
影响因子：
3.7
通讯作者：
Yong‐Hoon Cho;G. Gainer;J. B. Lam;J. Song;W. Yang;W. Jhe
中科院分区：
文献类型：
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作者：
Yong‐Hoon Cho;G. Gainer;J. B. Lam;J. Song;W. Yang;W. Jhe
本文对Al x Ga 1− xN外延层（0<~ x<~ 0. 6)通过光致发光（PL）、PL激发和时间分辨PL光谱。对于Al含量高的Al x Ga 1− x N，我们观察到了异常的PL温度依赖性：（i）随着温度的升高，PL峰的能量移动（减少-增加-减少）和（ii）“倒S形”光谱宽度加宽（增加-减少-增加）。我们观察到，在显示异常温度诱导发射行为的温度区域，通过抑制非辐射过程，积分PL强度的热降低被抑制，有效寿命被增强，反映了上级发光效率。所有这些功能增强的Al摩尔分数的增加。从这些结果来看，反常的温度诱导发射位移归因于Al含量大的Al x Ga 1− x N外延层中合金势不均匀性引起的能量尾态。
We present a comprehensive study of the optical characteristics of Al x Ga 1− x N epilayers (0<~ x<~ 0. 6) by means of photoluminescence (PL), PL excitation, and time-resolved PL spectroscopy. For Al x Ga 1− x N with large Al content, we observed an anomalous PL temperature dependence:(i) an “S-shaped” PL peak energy shift (decrease-increase-decrease) and (ii) an “inverted S-shaped” spectral width broadening (increase-decrease-increase) with increasing temperature. We observed that the thermal decrease in integrated PL intensity was suppressed and the effective lifetime was enhanced in the temperature region showing the anomalous temperature-induced emission behavior, reflecting superior luminescence efficiency by suppressing nonradiative processes. All these features were enhanced as the Al mole fraction was increased. From these results, the anomalous temperature-induced emission shift is attributed to energy tail states due to alloy potential inhomogeneities in the Al x Ga 1− x N epilayers with large Al content.