Growth of high density self-organized (In,Ga)As quantum dots with ultranarrow photoluminescence linewidths using buried In(Ga,Al)As stressor dots

Krishna, S.; Sabarinathan, Jayshri; Linder, K. K.; Bhattacharya, P.; Lita, B.; Goldman, R. S.

doi:10.1116/1.591413

“…It can be seen that when the base equals twice the island height the energy is a minimum. This result is consistent with experimental observation [9]. It is important to note that the total energy of the system would include the wetting layer strain energy and one has to then account for the dot density as well.…”

Section: Resultssupporting

confidence: 78%

“…The base of the pyramid is about twice the height [8,9]. This description of the self-assembled dots is; however, very qualitative since there is a considerable variation in the size and shape.…”

Section: Theoretical Modelmentioning

confidence: 99%

A Theoretical Study of Structural Disorder and Photoluminescence Linewidth in InGaAs/GaAs Self Assembled Quantum Dots

Lin

¹

,

Jiang

²

,

Singh

³

2001

MRS Proc.

0

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The past few years have seen considerable efforts in growth and device application of selfassembled 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; (2) an 8-band k -p method to calculate the electronic spectra. We present results on the strain energy per unit cell for various distributions of InAs/GaAs quantum dots and relate them to published experimental results. In particular we examine uncovered InAs/GaAs dots and show that in the uncovered state a welldefined minimum exists in the configuration energy plot. The minimum corresponds to the size that agrees well with experiments.

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“…Nevertheless a clear minimum arises in the configuration energy plots in both cases at 62 A dot height. This value is remarkably close to empirical observation [9]. However, due to entropy consideration we do not expect all dots to have this minimum energy size.…”

Section: Resultssupporting

confidence: 67%

A Theoretical Study of Structural Disorder and Photoluminescence Linewidth in InGaAs/GaAs Self Assembled Quantum Dots

Lin

¹

,

Jiang

²

,

Singh

³

2001

MRS Proc.

0

View full text Add to dashboard Cite

The past few years have seen considerable efforts in growth and device application of selfassembled 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; (2) an 8-band k -p method to calculate the electronic spectra. We present results on the strain energy per unit cell for various distributions of InAs/GaAs quantum dots and relate them to published experimental results. In particular we examine uncovered InAs/GaAs dots and show that in the uncovered state a welldefined minimum exists in the configuration energy plot. The minimum corresponds to the size that agrees well with experiments.

show abstract

“…Even when compared to large-area self-assembled QD ensembles grown using methods or structures designed to enhance uniformity and minimize luminescence linewidth, the EL from the NSL-fabricated QDs presented here compares favorably, in terms of emission linewidth. [28][29][30] Only when compared to limited-area patterned QDs formed with advanced lithographic techniques do we see our NSL-patterned QDs exhibiting broader emission linewidths. 17 Though PL and EL emission from the samples is weak, there are multiple avenues available for improving emission efficiency.…”

mentioning

confidence: 93%