Tuning self-assembled InAs quantum dots by rapid thermal annealing

Malik, Surama; Roberts, Christine Cardinal; Murray, R.; Pate, M.A.

doi:10.1063/1.119763

Cited by 240 publications

(156 citation statements)

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“…We note that the morphology of a single QD is impossible to be precisely controlled in experiments. However, the statistical properties of QDEs maybe well controlled [39], therefore it provides an interesting arena in future to study the relationship between these parameters and the growth environments, such as temperature, pressure, etc.…”

Section: Qdsmentioning

confidence: 99%

Statistical properties of exciton fine structure splitting and polarization angles in quantum dot ensembles

et al. 2014

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We propose an effective model to describe the statistical properties of exciton fine structure splitting (FSS) and polarization angle of quantum dot ensembles (QDEs). We derive the distributions of FSS and polarization angle for QDEs and show that their statistical features can be fully characterized using at most three independent measurable parameters. The effective model is confirmed using atomistic pseudopotential calculations as well as experimental measurements for several rather different QDEs. The model naturally addresses three fundamental questions that are frequently encountered in theories and experiments: (I) Why the probability of finding QDs with vanishing FSS is generally very small? (II) Why FSS and polarization angle differ dramatically from QD to QD? and (III) Is there any direct connection between FSS, optical polarization and the morphology of QDs? The answers to these fundamental questions yield a completely new physical picture for understanding optical properties of QDEs.

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Section: Qdsmentioning

confidence: 99%

Statistical properties of exciton fine structure splitting and polarization angles in quantum dot ensembles

et al. 2014

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“…This behavior results in an increase of the frequency of the optical emission (blueshift), a phenomenon which has been experimentally observed. 17,18,19,20 The figure shows that, for τ = 6, the QD gap is about 7% larger than for τ = 0.…”

Section: Resultsmentioning

confidence: 96%

“…The third line indicates that chemical disorder significantly enhances (by about 40%, in the case con-sidered here) the oscillator strength f QD of the fundamental optical transition, in qualitative agreement with experimental results. 17,18 This effect is primarily due to the modification of the strain field due to chemical disorder, because in the strainunaffected case f QD does not significantly vary.…”

Section: Resultsmentioning

confidence: 99%

“…In most growth processes, nonuniform Ga incorporation in nominally InAs QDs has been reported. 2,3,4,5,6,7,8,9,10,11,12,13,14,15,16 Photoluminescence studies of annealed QDs have shown a blue-shift of their emission line, 5,6,17,18,19 which was suggested to reflect diffusion of Ga atoms from the matrix material into the QD during annealing. However, it is not clear to which extent the blue-shift is a consequence of chemical substitution (bulk GaAs has a wider band gap than InAs), and to which extent it is due to reduced strain in the QD after Ga interdiffusion, which also causes a band-gap widening.…”

Section: Introductionmentioning

confidence: 99%

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Effect of post-growth annealing on the optical properties of InAs/GaAs quantum dots: A tight-binding study

Santoprete

Kratzer

Scheffler

et al. 2007

Journal of Applied Physics

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We present an atomistic study of the strain field, the one-particle electronic spectrum and the oscillator strength of the fundamental optical transition in chemically disordered InxGa1−xAs pyramidal quantum dots (QDs). Interdiffusion across the interfaces of an originally "pure" InAs dot buried in a GaAs matrix is simulated through a simple model, leading to atomic configurations where the abrupt hetero-interfaces are replaced by a spatially inhomogeneous composition profile x. Structural relaxation and the strain field calculations are performed through the Keating valence force field (VFF) model, while the electronic and optical properties are determined within the empirical tight-binding (ETB) approach. We analyze the relative impact of two different aspects of the chemical disorder, namely: (i) the effect of the strain relief inside the QD, and (ii) the purely chemical effect due to the group-III atomic species interdiffusion. We find that these effects may be quantitatively comparable, significantly affecting the electronic and optical properties of the dot. Our results are discussed in comparison with recent luminescence studies of intermixed QDs.

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“…1 Photoluminescence ͑PL͒ investigations suggest blueshift in the interband energy and narrowing of the PL linewidth after thermal annealing. [2][3][4] Although the reasons for this shift have been investigated from a microstructural point of view, 5,6 little attention has been paid to the effects of thermal annealing on compositional change within QDs.…”

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confidence: 99%