A Theoretical Study of Structural Disorder and Photoluminescence Linewidth in InGaAs/GaAs Self Assembled Quantum Dots
MICHIGAN UNIV ANN ARBOR DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
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The past few years have seen considerable efforts in growth and device application of self- assembled quantum dots. However, the photoluminescence PL linewidth, which represents structural fluctuations in dot sizes, is still in the range of 30-50 meV. This large linewidth has deleterious effects on devices such as lasers based on self-assembled dots. In this paper we will examine the configuration-energy diagram of self-assembled dots. Our formalism is based on 1 an atomistic Monte Carlo method which allows us to find the minimum energy configuration and strain tensors as well as intermediate configurations of dots and 2 an 8 bands k-p method to calculate the electronic spectra. We present results on the strain energy per unit cell for various distributions of InAsGaAs quantum dots and relate them to published experimental results. In particular we examine uncovered InAsGaAs dots and show that in the uncovered state a well-defined minimum exists in the configuration energy plot. The minimum corresponds to the size that agrees well with experiments.
- Solid State Physics