Mechanism of stress relaxation in (0001) InGaN/GaN via formation of V-shaped dislocation half-loops

Lobanova, A.V.; Kolesnikova, A. L.; Романов, А. Е.; Karpov, S. Yu.; Rudinsky, M. E.; Yakovlev, E.V.

doi:10.1063/1.4824835

Cited by 50 publications

(21 citation statements)

References 32 publications

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“…The compressive stress in Sample B is slightly higher than that in Sample A. It is well known that dislocation can release stress [31], so the stress state is consistent with the results of HRXRD. Figure 4a,b are the optical emission micrographs for Samples A and B at a 1 mA injection current, respectively.…”

Section: Methodssupporting

confidence: 84%

Using a Multi-Layer Stacked AlGaN/GaN Structure to Improve the Current Spreading Performance of Ultraviolet Light-Emitting Diodes

Wang

Zhang

et al. 2020

Materials

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To obtain excellent current spreading performance of ultraviolet light-emitting diodes (UVLEDs), a 60-period stacked Si modulation-doped n-AlGaN/u-GaN structure is proposed to replace the traditional n-AlGaN structure. The high-resolution X-ray diffraction ω-scan rocking curves show that the periodic growth of AlGaN and GaN layers plays a positive role in reducing dislocation density. Compared with the conventional UV light-emitting diodes (LEDs), light emission micrographs of devices with a multi-layer stacked n-AlGaN/u-GaN structure reveal higher brightness and a more uniform distribution. In addition, the output power and external quantum efficiency under a 20-mA injection current are increased by 22% and 26.5%, respectively. Experimental and simulation results indicate that a multi-layer stacking structure can alleviate the current crowding effect in four ways:(1) a reduction in dislocation density; (2) replacement of quasi-two-dimensional electron transport with electronic bulk transport to enhance electron mobility; (3) an increase in electron concentration without improving the impurity concentration; and (4) a weakening of the electron scattering effect by reducing the impurity concentration.

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Section: Methodssupporting

confidence: 84%

Using a Multi-Layer Stacked AlGaN/GaN Structure to Improve the Current Spreading Performance of Ultraviolet Light-Emitting Diodes

Wang

Zhang

et al. 2020

Materials

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“…In turn, the mismatch may evoke stress relaxation in InGaN QWs accompanied by misfit dislocation formation, if the well thickness exceeds its critical value. Estimation of the (0001)InGaN/GaN critical thickness shows that it only becomes comparable with typical QW widths in the green/yellow spectral range [14]. Point defect generation defect generation and parasitic impurity incorporation are also expected to be enhanced at high InN fractions because of the lower growth temperatures normally used for increasing the indium content in InGaN QWs [15].…”

Section: Introductionmentioning

confidence: 99%

Effect of Carrier Localization on Recombination Processes and Efficiency of InGaN-Based LEDs Operating in the “Green Gap”

Karpov¹

2018

Applied Sciences

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A semi-empirical model of carrier recombination accounting for hole localization by composition fluctuations in InGaN alloys is extended to polar and nonpolar quantum-well structures. The model provides quantitative agreement with available data on wavelength-dependent radiative and Auger recombination coefficients in polar LEDs. Comparison of calculated internal quantum efficiencies of polar and nonpolar LEDs enables an assessment of the roles of carrier localization, quantum-confined Stark effect, and native material properties for the efficiency decline in the "green gap".

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“…This may lead to stress relaxation via dislocation formation in the QWs, as a prominent lattice-mismatch with the surrounding GaN layers arises. 7 In addition, higher In content is normally achieved by lowering the InGaN growth temperature, 8 which favors point defect formation. 9 Both, extended and point defects should promote Shockley-Read-Hall (SRH) recombination, 10 thus reducing LED efficiency.…”

mentioning

confidence: 99%

Temperature-dependent recombination coefficients in InGaN light-emitting diodes: Hole localization, Auger processes, and the green gap

Nippert

Karpov²,

Callsen

et al. 2016

Applied Physics Letters

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We obtain temperature-dependent recombination coefficients by measuring the quantum efficiency and differential carrier lifetimes in the state-of-the-art InGaN light-emitting diodes. This allows us to gain insight into the physical processes limiting the quantum efficiency of such devices. In the green spectral range, the efficiency deteriorates, which we assign to a combination of diminishing electronhole wave function overlap and enhanced Auger processes, while a significant reduction in material quality with increased In content can be precluded. Here, we analyze and quantify the entire balance of all loss mechanisms and highlight the particular role of hole localization.

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Mechanism of stress relaxation in (0001) InGaN/GaN via formation of V-shaped dislocation half-loops

Cited by 50 publications

References 32 publications

Using a Multi-Layer Stacked AlGaN/GaN Structure to Improve the Current Spreading Performance of Ultraviolet Light-Emitting Diodes

Using a Multi-Layer Stacked AlGaN/GaN Structure to Improve the Current Spreading Performance of Ultraviolet Light-Emitting Diodes

Effect of Carrier Localization on Recombination Processes and Efficiency of InGaN-Based LEDs Operating in the “Green Gap”

Temperature-dependent recombination coefficients in InGaN light-emitting diodes: Hole localization, Auger processes, and the green gap

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