Magnetospectroscopy of excited states in charge-tunable GaAs/AlGaAs [111] quantum dots
Magnetospectroscopy of excited states in charge-tunable GaAs/AlGaAs [111] quantum dots
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DOI：
10.1103/physrevb.93.245412
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发表时间：
2016-06-15
影响因子：
3.7
通讯作者：
Urbaszek, B.
中科院分区：
文献类型：
--
作者：
Durnev, M. V.;Vidal, M.;Urbaszek, B.
本文对液滴外延生长的无应变（111）GaAs/AlGaAs量子点中的高电荷和高激发电子空穴配合物进行了实验和理论研究。我们研究了其中一个载流子处于激发态的配合物，即“热”trions X-*和X+*，以及双负电荷激子X2-。我们在法拉第几何中的单个量子点上进行了磁光致发光实验，揭示了每个激发电子-空穴配合物的特征发射模式，这与在（001）生长的量子点中观察到的光致发光光谱有很大不同。我们提出了X-*、X+*和X（2-）配合物的精细结构和磁光发光光谱的详细理论，这些配合物是由电子-空穴库仑交换相互作用和重空穴混合之间的相互作用所控制的，这些量子点具有三角对称的特征。通过实验与理论的比较，可以精确地识别电荷状态，提取占据激发态的载流子的电子-空穴交换相互作用常数和g因子。
We present a combined experimental and theoretical study of highly charged and excited electron-hole complexes in strain-free (111) GaAs/AlGaAs quantum dots grown by droplet epitaxy. We address the complexes with one of the charge carriers residing in the excited state, namely, the "hot" trions X-* and X+*, and the doubly negatively charged exciton X2-. Our magnetophotoluminescence experiments performed on single quantum dots in the Faraday geometry uncover characteristic emission patterns for each excited electron-hole complex, which are very different from the photoluminescence spectra observed in (001)-grown quantum dots. We present a detailed theory of the fine structure and magnetophotoluminescence spectra of X-*, X+*, and X(2-)complexes, governed by the interplay between the electron-hole Coulomb exchange interaction and the heavy-hole mixing, characteristic for these quantum dots with a trigonal symmetry. Comparison between experiment and theory allows for precise charge state identification, as well as extraction of electron-hole exchange interaction constants and g factors for the charge carriers occupying excited states.