Effects of dislocations on the luminescence of GaN/InGaN multi-quantum-well light-emitting-diode layers

Choi, Yoo Seong; Park, J.-H; Kim, S.-S; Song, Ho‐Jun; Lee, S.-H; Jung, Jong-Je; Lee, B.-T

doi:10.1016/j.matlet.2004.03.021

Cited by 14 publications

(6 citation statements)

References 12 publications

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“…3(b), the PL spectra of those seven regions under excitation of 137 W/cm 2 are shown. The PL intensity decreased as the size of the DSDRs increased, which is fairly consistent with previous reports on microscopic PL intensity imaging [8,9].…”

Section: Pl Analyses On Defective Regionssupporting

confidence: 92%

“…The optical power decreased with the area ratio of the DSDRs at a given injection current. Choi et al reported that the dark spot area increased with the dislocation density in microscopic CL mapping images [8]. The area ratio of the DSDRs could be correlated with defect densities in the LED chip, and the increase of the density of nonradiative recombination centers with the DSDR area resulted in the degradation of the optical properties depending on the area ratio of the DSDRs.…”

Section: I-l Characteristics Of Led Chips With Dsdrsmentioning

confidence: 99%

“…They obtained PL images of the compound semiconductor wafers using a CCD camera under various band-pass filtering conditions, with an expanded excitation laser beam exposing over a wafer. However, only few reports have been published on PL imaging of III-V compound semiconductor wafers, excluding the studies on spatial PL and cathodoluminescence (CL) imaging and mapping at the microscopic scale [7][8][9], whereas a lot of research has been recently performed on Si-based photovoltaic wafers and SiC wafers for defect recognition [10,11].…”

Section: Introductionmentioning

confidence: 99%

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Properties of Defective Regions Observed by Photoluminescence Imaging for GaN-Based Light-Emitting Diode Epi-Wafers

Kim¹,

Kim²,

Kim³

et al. 2015

Journal of the Optical Society of Korea

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A photoluminescence (PL) imaging method using a vision camera was employed to inspect InGaN/GaN quantum-well light-emitting diode (LED) epi-wafers. The PL image revealed dark spot defective regions (DSDRs) as well as a spatial map of integrated PL intensity of the epi-wafer. The Shockley-Read-Hall (SRH) nonradiative recombination coefficient increased with the size of the DSDRs. The high nonradiative recombination rates of the DSDRs resulted in degradation of the optical properties of the LED chips fabricated at the defective regions. Abnormal current-voltage characteristics with large forward leakages were also observed for LED chips with DSDRs, which could be due to parallel resistances bypassing the junction and/or tunneling through defects in the active region. It was found that the SRH nonradiative recombination process was dominant in the voltage range where the forward leakage by tunneling was observed. The results indicated that the DSDRs observed by PL imaging of LED epi-wafers were high density SRH nonradiative recombination centers which could affect the optical and electrical properties of the LED chips, and PL imaging can be an inspection method for evaluation of the epi-wafers and estimation of properties of the LED chips before fabrication.

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Section: Pl Analyses On Defective Regionssupporting

confidence: 92%

Section: I-l Characteristics Of Led Chips With Dsdrsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Properties of Defective Regions Observed by Photoluminescence Imaging for GaN-Based Light-Emitting Diode Epi-Wafers

Kim¹,

Kim²,

Kim³

et al. 2015

Journal of the Optical Society of Korea

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“…The TDs in the GaN film play the role of non-radiative recombination centers to deteriorate the luminescence efficiency 36 . The strong band edge emission demonstrates that the optical quality of the HVPE GaN layer is good and the TDs density is low.…”

Section: Resultsmentioning

confidence: 99%

Direct growth of freestanding GaN on C-face SiC by HVPE

Tian

Shao

et al. 2015

Sci Rep

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In this work, high quality GaN crystal was successfully grown on C-face 6H-SiC by HVPE using a two steps growth process. Due to the small interaction stress between the GaN and the SiC substrate, the GaN was self-separated from the SiC substrate even with a small thickness of about 100 μm. Moreover, the SiC substrate was excellent without damage after the whole process so that it can be repeatedly used in the GaN growth. Hot phosphoric acid etching (at 240 °C for 30 min) was employed to identify the polarity of the GaN layer. According to the etching results, the obtained layer was Ga-polar GaN. High-resolution X-ray diffraction (HRXRD) and electron backscatter diffraction (EBSD) were done to characterize the quality of the freestanding GaN. The Raman measurements showed that the freestanding GaN film grown on the C-face 6H-SiC was stress-free. The optical properties of the freestanding GaN layer were determined by photoluminescence (PL) spectra.

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“…The TEM and EDX mapping results suggest that the MQWs of the LED epitaxial structure have been strongly affected after stress, especially close to the p side. In general, threading dislocations (TDs) in InGaN/GaN multi-quantum-well (MQW) active structures would act as nonradiative recombination centers and degrade the emission intensity [44,45], which strongly contribute to the leakage current of forward and reverse I-V regions in LEDs [46,47]. The electrical and optical properties of the InGaN/GaN MQWs tend to decrease with increasing the dislocation densities [48].…”

Section: Resultsmentioning

confidence: 99%

The influence of point defects on AlGaN-based deep ultraviolet LEDs

Almalki

Yang

et al. 2020

Journal of Alloys and Compounds

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AlGaN-based deep ultraviolet LEDs with high Al composition are promising for many applications, including air-or water-purification, fluorescence sensing, etc. However, to realize their full potential, it is important to understand the impact of the point defects on the device performance. Here, we investigate the defects in the 265nm AlGaN-based deep ultraviolet LEDs after degradation systematically with a combination of different analytical technologies. The results show that point defects increase after the degradation. The generated defects during the stress lead to a carrier redistribution in the active region and the induced point defects during the degradation are located within the multi-quantum wells (MQWs) region, especially in the first quantum well near the p side of the LED chip. The dislocation lines in the MQWs region were also observed after the degradation, which can lead to the Mg diffusion along the dislocation line. These findings are important to understand the defects in AlGaN quantum wells and further improve AlGaN-based deep ultraviolet LEDs' performance.

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Effects of dislocations on the luminescence of GaN/InGaN multi-quantum-well light-emitting-diode layers

Cited by 14 publications

References 12 publications

Properties of Defective Regions Observed by Photoluminescence Imaging for GaN-Based Light-Emitting Diode Epi-Wafers

Properties of Defective Regions Observed by Photoluminescence Imaging for GaN-Based Light-Emitting Diode Epi-Wafers

Direct growth of freestanding GaN on C-face SiC by HVPE

The influence of point defects on AlGaN-based deep ultraviolet LEDs

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