Temperature and excitation density dependence of the photoluminescence from annealed InAs/GaAs quantum dots
Temperature and excitation density dependence of the photoluminescence from annealed InAs/GaAs quantum dots
复制标题
DOI：
10.1103/physrevb.67.245318
复制
发表时间：
2003-06-27
影响因子：
3.7
通讯作者：
Murray, R
中科院分区：
文献类型：
--
作者：
Le Ru, EC;Fack, J;Murray, R
采用快速热退火方法制备了一系列基态发射范围为1.05 ~ 1.35 eV的InAs/GaAs量子点样品。这组退火的样品，都具有相同的密度，使我们能够研究的势垒高度的光致发光（PL）的温度依赖性的影响。综合PL遵循阿伦尼乌斯型行为，激活能与势垒高度匹配。然而，淬火发生在较低的温度作为势垒高度降低。这些数据的建模使我们能够了解决定发生淬火的临界温度的重要机制。我们还提出了一个详细的调查在不同温度下的光致发光的激发密度依赖性。在相对较低的激发下，这种依赖性在10 K时是线性的，并且随着温度的增加和载流子从点逃逸而变得越来越超线性并最终二次。然而，在高激发下，相关性保持线性，即使在高温和淬火的活化能是不同的。我们表明，所有这些结果可以通过考虑独立的捕获和逃逸的电子和空穴的点来理解。
Using rapid thermal annealing, we fabricated a series of InAs/GaAs quantum dot samples with ground-state emission ranging from 1.05 eV to 1.35 eV. This set of annealed samples, all having the same density, allows us to study the influence of the barrier height on the temperature dependence of the photoluminescence (PL). The integrated PL follows an Arrhenius-type behavior, with activation energies matching the barrier heights. However, the quenching occurs at lower temperatures as the barrier height decreases. The modeling of these data enables us to understand the important mechanisms determining the critical temperature where the quenching occurs. We also present a detailed investigation into the excitation density dependence of the photoluminescence at different temperatures. Under relatively low excitation, this dependence is linear at 10 K, and becomes increasingly superlinear and eventually quadratic as the temperature is increased and carriers escape from the dots. However, under high excitation, the dependence remains linear even at high temperatures and the activation energy for quenching is different. We show that all these results can be understood by considering the independent capture and escape of electrons and holes in the dots.