Structural defects in bulk GaN

Liliental‐Weber, Z.; Reis, Roberto dos; Mancuso, Monique; Song, Chengyu; Grzegory, I.; Porowski, S.; Boćkowski, Michał

doi:10.1016/j.jcrysgro.2014.06.022

Cited by 6 publications

(7 citation statements)

References 24 publications

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“…The remaining gallium, which did not crystallize into In x Ga 1– x N, should then stay as a separate phase inside the void. Such precipitations of amorphous gallium were observed inside voids found in GaN crystals grown from high nitrogen pressure solution …”

Section: Results and Discussionmentioning

confidence: 99%

“…Such precipitations of amorphous gallium were observed inside voids found in GaN crystals grown from high nitrogen pressure solution. 23 The preserved areas of the QWs between the void exhibit much reduced HAADF intensity indicating a lowered In content, suggesting the diffusion of In out of the QW (Figure 5a). Also, the amount of indium found in the In-rich phases inside the final voids indicates that In atoms must diffuse to the void from a larger volume fraction of the QW rather than the volume of a final void itself.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Role of Metal Vacancies in the Mechanism of Thermal Degradation of InGaN Quantum Wells

Smalc-Koziorοwska

Grzanka

Lachowski

et al. 2021

ACS Appl. Mater. Interfaces

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In this work, we study the thermal degradation of In-rich In x Ga1–x N quantum wells (QWs) and propose explanation of its origin based on the diffusion of metal vacancies. The structural transformation of the In x Ga1–x N QWs is initiated by the formation of small initial voids created due to agglomeration of metal vacancies diffusing from the layers beneath the QW. The presence of voids in the QW relaxes the mismatch stress in the vicinity of the void and drives In atoms to diffuse to the relaxed void surroundings. The void walls enriched in In atoms are prone for thermal decomposition, what leads to a subsequent disintegration of the surrounding lattice. The phases observed in the degraded areas of QWs contain voids partly filled with crystalline In and amorphous material, surrounded by the rim of high In-content In x Ga1–x N or pure InN; the remaining QW between the voids contains residual amount of In. In the case of the In x Ga1–x N QWs deposited on the GaN layer doped to n-type or on unintentionally doped GaN, we observe a preferential degradation of the first grown QW, while doping of the underlying GaN layer with Mg prevents the degradation of the closest In x Ga1–x N QW. The reduction in the metal vacancy concentration in the In x Ga1–x N QWs and their surroundings is crucial for making them more resistant to thermal degradation.

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Section: Results and Discussionmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Role of Metal Vacancies in the Mechanism of Thermal Degradation of InGaN Quantum Wells

Smalc-Koziorοwska

Grzanka

Lachowski

et al. 2021

ACS Appl. Mater. Interfaces

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“…This might suggest that the interfacial area is somehow weaker than the surrounding substrate or the homoepitaxial layer. These authors 68) using CBED studies showed that these HVPE layers have Ga growth polarity repeating the sub-strate polarity. Long dislocations observed in the HNPS-MFS layers grown on the HVPE substrates were not observed in the HVPE layers grown on the ammonothermal substrates.…”

Section: Hvpe Growth On Ammonothermal Substratesmentioning

confidence: 96%

“…16,17) The main goal of this procedure is to obtain thick layers that can be later sliced for the application in devices. TEM studies by Liliental-Weber et al 68) of 90-µm-thick HNPS-MFS layers grown on 50-µmthick HVPE substrate show that the majority of dislocations present in the substrate propagate to the HNPS-MFS grown layer. Some of them interact with each other; therefore, at the sample surface density of dislocations is much smaller.…”

Section: High Pressure Growth On Hvpe Substratementioning

confidence: 99%

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Structural defects in GaN revealed by transmission electron microscopy

Liliental‐Weber

2014

Jpn. J. Appl. Phys.

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This paper reviews the various types of structural defects observed by transmission electron microscopy in GaN heteroepitaxial layers grown on foreign substrates and homoepitaxial layers grown on bulk GaN substrates. The structural perfection of these layers is compared to the platelet self-standing crystals grown by high nitrogen pressure solution. Defects in undoped and Mg doped GaN are discussed. Some models explaining the formation of inversion domains in heavily Mg doped layers that are possible defects responsible for the difficulties of p-doping in GaN are also reviewed.

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