Evidence of nanoscale Anderson localization induced by intrinsic compositional disorder in InGaN/GaN quantum wells by scanning tunneling luminescence spectroscopy
Evidence of nanoscale Anderson localization induced by intrinsic compositional disorder in InGaN/GaN quantum wells by scanning tunneling luminescence spectroscopy
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DOI：
10.1103/physrevb.98.045305
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发表时间：
2018-07-19
影响因子：
3.7
通讯作者：
Peretti, J.
中科院分区：
文献类型：
--
作者：
Hahn, W.;Lentali, J. -M.;Peretti, J.
我们给出了由InGaN/GaN量子阱的本征合金成分无序引起的Anderson局域化的直接实验证据。我们的方法依赖于对电子从扫描隧道显微镜针尖注入到近表面单量子阱中的局部注入下的发光光谱的测量。发射线形状的波动是在几纳米尺度上观察到的。解决了单一局域态发射峰窄的问题。在局域化景观理论框架下的计算提供了成分起伏产生的有效禁闭势图。这一理论很好地解释了观察到的纳米尺度载流子局域化和这些安德森型局域态的能量。局域态发射的能量扩散与通常观察到的InGaN/GaN量子阱结构的很宽的光致或电致发光光谱是一致的。
We present direct experimental evidence of Anderson localization induced by the intrinsic alloy compositional disorder of InGaN/GaN quantum wells. Our approach relies on the measurement of the luminescence spectrum under local injection of electrons from a scanning tunneling microscope tip into a near-surface single quantum well. Fluctuations in the emission line shape are observed on a few-nanometer scale. Narrow emission peaks characteristic of single localized states are resolved. Calculations in the framework of the localization landscape theory provide the effective confining potential map stemming from composition fluctuations. This theory explains well the observed nanometer scale carrier localization and the energies of these Anderson-type localized states. The energy spreading of the emission from localized states is consistent with the usually observed very broad photo- or electroluminescence spectra of InGaN/GaN quantum well structures.