Asymmetry of charge relaxation times in quantum dots: The influence of degeneracy
Asymmetry of charge relaxation times in quantum dots: The influence of degeneracy
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DOI：
10.1209/0295-5075/106/47002
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发表时间：
2014-05-01
期刊：
影响因子：
1.8
通讯作者：
Lorke, A.
中科院分区：
文献类型：
--
作者：
Beckel, A.;Kurzmann, A.;Lorke, A.
使用时间分辨跨导光谱，我们研究了嵌入场效应晶体管结构中的二维电子气 (2DEG) 和自组装量子点 (QD) 之间的隧道动力学。我们发现电子从 2DEG 隧道进入量子点受与相反过程不同的时间常数控制，即。即，从 QD 到 2DEG 的隧道效应。这种不对称性是库仑相互作用的明显特征，即使由于不均匀展宽而无法在能量上解析各个状态，也可以确定量子点轨道的简并性。我们的实验数据可以通过主方程方法进行定性解释。版权所有 (C) EPLA，2014
Using time-resolved transconductance spectroscopy, we study the tunneling dynamics between a two-dimensional electron gas (2DEG) and self-assembled quantum dots (QDs), embedded in a field-effect transistor structure. We find that the tunneling of electrons from the 2DEG into the QDs is governed by a different time constant than the reverse process, i. e., tunneling from the QDs to the 2DEG. This asymmetry is a clear signature of Coulomb interaction and makes it possible to determine the degeneracy of the quantum-dot orbitals even when the individual states cannot be resolved energetically because of inhomogeneous broadening. Our experimental data can be qualitatively explained within a master-equation approach. Copyright (C) EPLA, 2014