Theory of reduced built-in polarization field in nitride-based quantum dots

Schulz, Stefan; O’Reilly, Eoin P.

doi:10.1103/physrevb.82.033411

Cited by 75 publications

(51 citation statements)

References 19 publications

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“…2. The growth of QDs can therefore provide an additional route to field reduction in c plane III-N heterostructures, 52,53 as recently demonstrated experimentally. 54 Figures 3(c) and 3(d) depict the calculated built-in field in GaN/Al x In 1Àx N QW and QD structures, showing that a complete suppression of the built-in field can be achieved for x % 0:7 in both QW and QD structures, at the expense of reducing the initial energy gap difference between dot and barrier from $2.5 to $0:3 eV (Fig.…”

Section: Built-in Field Reductionmentioning

confidence: 91%

“…3(a) and 3(b) that the calculated built-in field is in both cases reduced in the QD structure compared to the QW case. This occurs both because of the reduced surface area of a dot compared to a QW (reduced area of induced surface charge) and also because of the reduction in the magnitude of e 11 and e 33 in the QD structure, 51,52 as seen in Fig. 2.…”

Section: Built-in Field Reductionmentioning

confidence: 99%

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Built-in field control in alloyedc-plane III-N quantum dots and wells

Miguel

Schulz

Healy

et al. 2011

Journal of Applied Physics

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Access to the full text of the published version may require a subscription. We investigate the degree to which the built-in electric field can be suppressed by employing polarization-matched barriers in III-N quantum well and dot structures grown along the c axis. Our results show that it is possible to take advantage of the opposite contributions to the built-in potential arising from the different possible combinations of wurtzite GaN, InN, and AlN when alloying the materials. We show that, for a fixed bandgap of the dot/well, optimal alloy compositions can be found that minimize the built-in field across the structure. We discuss and study the impact of different material parameters on the results, including the influence of nonlinear effects in the piezoelectric polarization. Structures grown with unstrained barriers and on GaN epilayers are considered, including discussion of the effects of constraints such as strain limits and alloy miscibility. Rights

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Section: Built-in Field Reductionmentioning

confidence: 91%

Section: Built-in Field Reductionmentioning

confidence: 99%

Built-in field control in alloyedc-plane III-N quantum dots and wells

Miguel

Schulz

Healy

et al. 2011

Journal of Applied Physics

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“…Please note that / p in an isolated QD is already significantly reduced compared to a QW structure of the same composition and height. 6 Therefore, the increase of jd~1 1 j 2 for small D further emphasizes the benefit of using QDs instead of QWs in optoelectronic devices. It should be noted that jd~1 1 j 2 > 1 for the ground state transition is a consequence of e 15 < 0.…”

mentioning

confidence: 95%

“…4 One strategy to reduce the built-in field in nitride-based optoelectronic devices is to replace QWs by quantum dots (QDs), since the built-in potential in a QD compared to a QW of the same height and composition is significantly reduced. 5,6 The In composition can, therefore, be increased in a QD compared to a QW, enabling efficient recombination to longer wavelengths. Different authors 7 have recently demonstrated that InGaN-QD-based LEDs and lasers, operating in the amber and green spectral region, show superior performance compared to their QW-based counterparts.…”

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confidence: 99%

Built-in field reduction in InGaN/GaN quantum dot molecules

Schulz¹,

O’Reilly

2011

Applied Physics Letters

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We use a tight-binding model to study the electronic structure of InGaN/GaN quantum dot molecules grown along the c-axis. This analysis is carried out as a function of the barrier thickness between the two non-identical dots. Our results show that the built-in field is effectively reduced in systems of coupled nitride quantum dots, leading to an increased spatial overlap of electron and hole wave functions compared to an isolated dot. This finding is in agreement with experimental data reported in the literature and is directly related to the behavior of the built-in potential outside an isolated dot. (C) 2011 American Institute of Physics. (doi:10.1063/1.3665069

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“…Biexcitons (exciton molecule) have also been theoretically demonstrated to play a significant role in further improving the LD performance [35]. Moreover, it has been shown both theoretically [36,37] and experimentally [16] that the piezoelectric field and resulting QCSE are significantly lower in InGaN/GaN QDs than in InGaN/GaN MQWs.…”

Section: Qd Lasersmentioning

confidence: 99%

III-Nitride-Based Quantum Dots and Their Optoelectronic Applications

Weng

Ling

et al. 2011

Nano-Micro Lett.

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During the last two decades, III-nitride-based quantum dots (QDs) have attracted great attentions for optoelectronic applications due to their unique electronic properties. In this paper, we first present an overview on the techniques of fabrication for III-nitride-based QDs. Then various optoelectronic devices such as QD lasers, QD light-emitting diodes (LEDs), QD infrared photodetectors (QDIPs) and QD intermediate band (QDIB) solar cells (SCs) are discussed. Finally, we focus on the future research directions and how the challenges can be overcome.

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Theory of reduced built-in polarization field in nitride-based quantum dots

Cited by 75 publications

References 19 publications

Built-in field control in alloyedc-plane III-N quantum dots and wells

Built-in field control in alloyedc-plane III-N quantum dots and wells

Built-in field reduction in InGaN/GaN quantum dot molecules

III-Nitride-Based Quantum Dots and Their Optoelectronic Applications

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