Correlation between growth interruption and indium segregation in InGaN MQWs

Dmukauskas, M.; Mickevičius, J.; Dobrovolskas, D.; Kadys, A.; Наргелас, С.; Тамулайтис, Г.

doi:10.1016/j.jlumin.2020.117103

Cited by 8 publications

(2 citation statements)

References 39 publications

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“…Based on secondary electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM), different groups report that V-defects have an open hexagonal inverted pyramid with {10-11} sidewalls [8] and could originate in the MQWs layer of the device due to the increase in the strain energy with increasing layer thickness and indium mole fraction [9] and also due to the relative low temperature used to grow InGaN QWs [10]. V-pit negatively impact the active region of the devices interrupting the periodic structure creating region with different well and barrier thicknesses also with different indium incorporation and concentration [11] from which a different barrier height in the pyramid plane of the V-pits with respect to (0001) surface plane occurs [12] thus altering the electrical and optical properties of the devices. In the literature, a comprehensive examination of the impact of V-pits on the electrical characteristics of GaN-based solar cells with high periodicity MQWs has not been presented so far.…”

Section: Introductionmentioning

confidence: 99%

Influence of V-pits on the electro-optical properties of high-periodicity InGaN MQWs

Nicoletto,

Caria,

Rampazzo

et al. 2024

Gallium Nitride Materials and Devices XIX

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We investigated the influence of V-pits on the turn-on voltage of GaN-based high periodicity multiple quantum wells (MQWs) solar cells with different thickness of the p-GaN layer. Experimental current-voltage characteristics indicate that the sample with the thinnest p-GaN layer presents an early turn-on, which is not present for samples with a thicker p-GaN layer. Focusing on the V-defects analysis, through scanning electron microscopy (SEM) we found no difference in the density and dimensions of V-pits between sample with different p-GaN thickness. Through TCAD Synopsys Sentaurus simulations, the main non-illuminated current-voltage characteristics are reproduced considering V-defects. The results indicate that V-pits play a dominant role in current conduction, especially for the devices with the thinnest p-GaN layer due to the insufficient V-pit planarization. For such devices V-pits penetrate the junctions, and locally put the MQWs region in closer connection to the p-side contact, resulting in the formation of localized short circuit paths. Finally, a Gaussian distribution of V-pits dimensions and depth is considered to reach a good matching of experimental data. Based on combined electrical analysis, microscopy investigation and 2D simulations, results provide insight on the role of V-pits on the electrical performance of GaN-based MQWs solar cells. The outcome of this work will be useful for the design of future high-periodicity quantum wells devices, ensuring the desired turn-on voltage and showing the existence of a tradeoff between the need of a thin p-GaN (to increase short-wavelength efficiency) and a thicker p-GaN, to avoid insufficient V-pit planarization.

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Section: Introductionmentioning

confidence: 99%

Influence of V-pits on the electro-optical properties of high-periodicity InGaN MQWs

Nicoletto,

Caria,

Rampazzo

et al. 2024

Gallium Nitride Materials and Devices XIX

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“…Numerous attempts have been demonstrated to improve the green LEDs efficiency by far [5][6][7][8][9]. For an example, by introducing In-surfactant in InGaN/GaN multi-quantum well (MQW) growth of green LEDs, particularly in QBs [10][11][12]. Such technique promoted sharp and smooth interfaces [13,14], while controlling threading dislocations (TDs) and indium out-diffusion [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Growth modification via indium surfactant for InGaN/GaN green LED

Taib¹,

Ahmad²,

Alias³

et al. 2023

Semicond. Sci. Technol.

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In this work, indium (In) was introduced as a surfactant during growth of high temperature GaN quantum barriers (QBs) and GaN interlayer of InGaN/GaN green LEDs. A reference LED grown without In-surfactant was also included for comparison. Results suggested that the LED growth was improved by introducing the In-surfactant, especially during the growth of the GaN interlayer. The In-surfactant improved the morphology of the interlayer, hence allowed it to serve as a good surface growth for the LED. Moreover, the LED showed the lowest FWHM of each XRD satellite peak when the In-surfactant was introduced in the GaN interlayer, suggesting an effective way to improve the multi-quantum wells (MQWs). The introduction of the In-surfactant in the GaN interlayer and GaN QBs growths shifted the emission wavelength of the corresponding LEDs towards red (λemission = 534 nm) with respect to the reference LED where λemission = 526 nm. Furthermore, the In-surfactant introduction reduced the forward voltage, Vf of the corresponding LEDs down to 4.56 V, compared to the reference LED with Vf of 5.33 V. It also allowed the LEDs to show faster carrier decay lifetime, and hence higher radiative recombination, particularly when it was introduced in the GaN interlayer growth.

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Effect of InGaN well layer growth rate upon photoluminescence of InGaN/GaN multiple-quantum-well structures

Wang

Shi

et al. 2022

Micro and Nanostructures

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Correlation between growth interruption and indium segregation in InGaN MQWs

Cited by 8 publications

References 39 publications

Influence of V-pits on the electro-optical properties of high-periodicity InGaN MQWs

Influence of V-pits on the electro-optical properties of high-periodicity InGaN MQWs

Growth modification via indium surfactant for InGaN/GaN green LED

Effect of InGaN well layer growth rate upon photoluminescence of InGaN/GaN multiple-quantum-well structures

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