Interdiffusion of In and Ga in InGaN/GaN multiple quantum wells

Chuo, Chang-Cheng; Lee, Chia Ming; Chyi, Jen Inn

doi:10.1063/1.1339991

Cited by 79 publications

(62 citation statements)

References 16 publications

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“…This is because bulk diffusion is negligible at typical growth temperatures, having much too high an energy barrier, such as ~3.4 eV for interdiffusion of In and Ga in InGaN 19 . However, the barriers are greatly reduced at surfaces.…”

Section: Resultsmentioning

confidence: 99%

“…If thermodynamic equilibrium were achieved throughout the NW, no core-shell structure would be observed. In reality, however, the alloy CPs in NWs are expected to be distinctly different from the equilibrium distribution, because bulk diffusion with an energy barrier of a few eVs 19 is negligible at typical growth temperatures. On the other hand, local equilibrium is often established in the near surface region due to the more rapid surface (and sub-surface) diffusion with a much smaller energy barrier in the order of 1 eV 20 or smaller.…”

Section: Introductionmentioning

confidence: 99%

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Simulation of self-assembled compositional core-shell structures in InxGa1−xN nanowires

et al. 2012

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We report the simulation of compositional core-shell structure formation in epitaxial InGaN nanowires (NWs) and its dependence on kinetic growth mode and epitaxial relation to substrate, based on atomistic-strain-model Monte Carlo simulations. On a lattice mismatched substrate, the layer-by-layer growth results in self-assembled core-shell structures with the core rich in the unstrained component (relative to the substrate), while the faceted growth mode leads to the strained core component, and both are distinctively different from the equilibrium composition profiles. Our simulation results explain the reason that all the existing core-shell alloy NWs grown by vapor-liquid-solid experiments have cores rich in the unstrained (or less strained) components is because they have been grown via the layer-bylayer mode, and more importantly suggest a possible route towards controlling the NW core-shell composition by altering growth mode and/or selecting substrate.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Simulation of self-assembled compositional core-shell structures in InxGa1−xN nanowires

et al. 2012

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“…From MEIS measurement, 10 we found that there exists a low-indium region near the bottom InGaN/ GaN interface. Since the atomic bond strength of GaN is quite larger than that of InN, 22,23 the thermal stability of the In-rich InGaN QW layer was improved when the region near the bottom interface became compositionally graded to the low-indium content InGaN layer with stronger bond, resulting in 1-nm-thick InGaN layer on GaN even after 10 s GI. 24 By increasing GI time from 0 to 10 s in four periods of MQW, structural properties of In-rich InGaN and LT-capped GaN layers were significantly improved and the integrated PL intensity increased, while the full width at half maximum ͑FWHM͒ decreased to 40 meV at 12 K. The PL peak showed a blueshift from 420 to 380 nm by increasing GI time, and more details on optical properties of the MQW can be found in Ref.…”

Section: B Decomposition and Mass Transport Processes During Gi In Imentioning

confidence: 99%

In-rich InGaN∕GaN quantum wells grown by metal-organic chemical vapor deposition

Kwon

Kim

et al. 2006

Journal of Applied Physics

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Growth mechanism of In-rich InGaN∕GaN quantum wells (QWs) was investigated. First, we examined the initial stage of InN growth on GaN template considering strain-relieving mechanisms such as defect generation, islanding, and alloy formation at 730 °C. It was found that, instead of formation of InN layer, defective In-rich InGaN layer with thickness fluctuations was formed to relieve large lattice mismatch over 10% between InN and GaN. By introducing growth interruption (GI) before GaN capping at the same temperature, however, atomically flat InGaN∕GaN interfaces were observed, and the quality of In-rich InGaN layer was greatly improved. We found that decomposition and mass transport processes during GI in InGaN layer are responsible for this phenomenon. There exists severe decomposition in InGaN layer during GI, and a 1-nm-thick InGaN layer remained after GI due to stronger bond strength near the InGaN∕GaN interface. It was observed that the mass transport processes actively occurred during GI in InGaN layer above 730 °C so that defect annihilation in InGaN layer was greatly enhanced. Finally, based on these experimental results, we propose the growth mechanism of In-rich InGaN∕GaN QWs using GI.

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“…The fact that we also observe a reduction of the In-content of the layers itself from x ¼ 0.33 to x ¼ 0.2 may be an evidence for an additional diffusion of In-atoms into the GaN barrier layers. The In-diffusion coefficient in c-InGaN is not known, however, the coefficient of In-diffusion in hexagonal material has been measured to be about 1 Â 10 --19 cm 2 s at 900 C with an activation energy of 3.4 eV [10]. Extrapolating the In-diffusion coefficient to the c-InGaN growth temperature of 600 C, we obtain a diffusion length of In during growth below 0.01 nm.…”

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confidence: 98%

Thermal Annealing of Cubic‐InGaN/GaN Double Heterostructures

Husberg

Khartchenko

et al. 2002

phys. stat. sol. (c)

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We have performed annealing experiments with c-InGaN/GaN double heterostructures in order to obtain information on the thermal stability and the formation process of In-rich clusters in the InGaN layers. While the as grown samples showed a dominating luminescence at about 2.3 eV, the annealed samples showed a new luminescence peak at 2.8-3.0 eV which may be due to a band gap emission of a regenerated layer with an In-content of about x ¼ 0.20. These results are corroborated by micro Raman spectroscopy. Our annealing experiments show that at elevated temperatures In-atoms can diffuse in c-InGaN layers while In-rich aggregates are stable at growth temperature.Introduction Recent X-ray diffraction and micro-Raman measurements gave first evidence of In-rich inclusions in c-InGaN layers [1]. Resonant Raman measurements show that the PL of these layers is related to In-rich nanometer-size quantum-dot (QD) like structures [2]. Investigations of the structure and photoluminescence (PL) from c-InGaN/GaN double heterostructures (DHs) showed the importance of the QD-like In-rich structures for the radiative recombination of electron hole pairs [3]. Evidence for radiative recombination of excitons localized in nanostructures such as In-rich clusters in cubic InGaN multiple quantum wells (MQWs) has also been reported in Ref. [4].In this paper we report on annealing experiments which were performed in order to obtain further insight into the formation process and the thermal stability of the In-rich clusters in our c-InGaN/GaN DHs.

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Interdiffusion of In and Ga in InGaN/GaN multiple quantum wells

Cited by 79 publications

References 16 publications

Simulation of self-assembled compositional core-shell structures in InxGa1−xN nanowires

Simulation of self-assembled compositional core-shell structures in InxGa1−xN nanowires

In-rich InGaN∕GaN quantum wells grown by metal-organic chemical vapor deposition

Thermal Annealing of Cubic‐InGaN/GaN Double Heterostructures

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