Atomistic pseudopotential calculations of thickness-fluctuation GaAs quantum dots
Atomistic pseudopotential calculations of thickness-fluctuation GaAs quantum dots
复制标题
DOI：
10.1103/physrevb.79.125329
复制
发表时间：
2009-03-01
影响因子：
3.7
通讯作者：
Zunger, Alex
中科院分区：
文献类型：
--
作者：
Luo, Jun-Wei;Bester, Gabriel;Zunger, Alex
利用原子经验赝势方法和组态相互作用计算了不同尺寸和不同延伸率的厚度涨落量子点的电子和光学性质。载流子被限制在GaAs/Al0.3Ga0.7As量子阱的厚度的单层波动与标称厚度之间的10和20单层。对于10单层厚度，我们发现几个受限的电子和空穴水平的主导重空穴字符穿透深入到障碍（平面外），远远超出的物理尺寸的单层步骤（平面内）。的空间范围的状态是强烈的随机合金波动的障碍，推动国家向富镓地区的接口。电子和空穴态的空间范围的相似性导致强的振子强度和丰富的光谱。激子以及双激子和trions（正的和负的）都显示出几条线的吸收，尽管在这些结构中给出了非常浅的限制电位。相关性对光谱的影响是剧烈的，会产生高度相关的状态，这些状态强烈偏离不相关的结果。
We calculate the electronic and optical properties of thickness-fluctuation quantum dots of different sizes and elongations using an atomistic empirical pseudopotential approach and configuration interaction. The carriers are confined by a monolayer fluctuation in the thickness of a GaAs/Al0.3Ga0.7As quantum well with a nominal thickness between 10 and 20 monolayers. For 10 monolayer thickness, we find several confined electron and hole levels of dominant heavy-hole character penetrating deep into the barrier (out of plane) and far beyond the physical dimension of the monolayer step (in-plane). The spatial extent of the states is strongly affected by the random-alloy fluctuations of the barrier, pushing the states toward Ga-rich regions of the interface. The similarity in the spatial extent of the electron and hole states leads to strong oscillator strength and a rich optical spectrum. The exciton as well as biexciton and trions (positive and negative) all show several lines in absorption despite the very shallow confinement potential given in these structures. The effects of correlations is drastic on the optical spectrum with the creation of highly correlated states that deviate strongly from the uncorrelated results.