3D numerical modeling of the carrier transport and radiative efficiency for InGaN/GaN light emitting diodes with V-shaped pits

Li, Chi Kang; Wu, Chen Kuo; Hsu, Chung Cheng; Li, Lu; Li, Heng; Lu, Tien‐Chang; Wu, Yuh Renn

doi:10.1063/1.4950771

Cited by 42 publications

(37 citation statements)

References 36 publications

(39 reference statements)

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“…52 two blue LEDs, a high-efficiency one with V f =2.89 V at 10 A.cm −2 and a high-power one with V f =3.10 V at 35 A.cm −2 , both values being in good agreement with the I-V characteristic predicted by the 1/u-Poisson-DD model. The remaining difference could be attributed to leakage paths via V-pit structures or dislocation lines, 53 to the absence in our modeling of tunneling in perpendicular transport, or to the internal temperature of real LED devices being higher than 300 K, leading to a lower V f .…”

Section: Electrical and Optical Properties Calculated From The Locmentioning

confidence: 93%

Localization landscape theory of disorder in semiconductors. III. Application to carrier transport and recombination in light emitting diodes

et al. 2017

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This paper introduces a novel method to account for quantum disorder effects into the classical drift-diffusion model of semiconductor transport through the localization landscape theory. Quantum confinement and quantum tunneling in the disordered system change dramatically the energy barriers acting on the perpendicular transport of heterostructures. In addition they lead to percolative transport through paths of minimal energy in the 2D landscape of disordered energies of multiple 2D quantum wells. This model solves the carrier dynamics with quantum effects self-consistently and provides a computationally much faster solver when compared with the Schrödinger equation resolution. The theory also provides a good approximation to the density of states for the disordered system over the full range of energies required to account for transport at room-temperature. The current-voltage characteristics modeled by 3-D simulation of a full nitride-based light-emitting diode (LED) structure with compositional material fluctuations closely match the experimental behavior of high quality blue LEDs. The model allows also a fine analysis of the quantum effects involved in carrier transport through such complex heterostructures. Finally, details of carrier population and recombination in the different quantum wells are given.

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Section: Electrical and Optical Properties Calculated From The Locmentioning

confidence: 93%

Localization landscape theory of disorder in semiconductors. III. Application to carrier transport and recombination in light emitting diodes

et al. 2017

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“…We setup the material parameters according to the indium map and assume that the electron and holes are generated by the absorption of optical excitation. Finally, the Poisson and drift-diffusion equations were solved self-consistently to obtain the in-plane carrier diffusion and radiative recombination distribution3536. As shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Three dimensional characterization of GaN-based light emitting diode grown on patterned sapphire substrate by confocal Raman and photoluminescence spectromicroscopy

Cheng

Chen

et al. 2017

Sci Rep

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We performed depth-resolved PL and Raman spectral mappings of a GaN-based LED structure grown on a patterned sapphire substrate (PSS). Our results showed that the Raman mapping in the PSS-GaN heterointerface and the PL mapping in the InxGa1−xN/GaN MQWs active layer are spatially correlated. Based on the 3D construction of E2(high) Raman peak intensity and frequency shift, V-shaped pits in the MQWs can be traced down to the dislocations originated in the cone tip area of PSS. Detail analysis of the PL peak distribution further revealed that the indium composition in the MQWs is related to the residual strain propagating from the PSS-GaN heterointerface toward the LED surface. Numerical simulation based on the indium composition distribution also led to a radiative recombination rate distribution that shows agreement with the experimental PL intensity distribution in the InxGa1−xN/GaN MQWs active layer.

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“…This finding indicated that GaN LEDs with optimized V-shaped pits under the proper growth condition of prestrained layers and less light absorption layers would provide a high-output power emission. The V f of samples A/B/C with large V-pits was lower than that of samples D/E/F with small V-pits because large V-pits facilitated a conducting path for carrier injection to MQWs [43]. In addition, samples with thicker n-type GaN layers exhibited lower V f because of the lower resistance in the thick n-type GaN layer.…”

Section: Optical and Electrical Properties Of Led Chips By El Measurementioning

confidence: 90%

Effect of Strains and V-Shaped Pit Structures on the Performance of GaN-Based Light-Emitting Diodes

Chen

2020

Crystals

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Strains and V-shaped pits are essential factors for determining the efficiency of GaN-based light-emitting diodes (LEDs). In this study, we systematically analyzed GaN LED structures on patterned sapphire substrates (PSSs) with two types of growth temperature employed for prestrained layers and three different thickness of n-type GaN layers by using cathodoluminescence (CL), microphotoluminescence (PL), and depth-resolved confocal Raman spectroscopy. The results indicated that V-pits formation situation can be analyzed using CL. From the emission peak intensity ratio of prestrained layers and multiple quantum wells (MQWs) in the CL spectrum, information regarding strain relaxation between prestrained layers and MQWs was determined. Furthermore, micro-PL and depth-resolved confocal Raman spectroscopy were employed to validate the results obtained from CL measurements. The growth conditions of prestrained layers played a dominant role in the determination of LED performance. The benefit of the thick layer of n-GaN was the strain reduction, which was counteracted by an increase in light absorption in thick n-type doped layers. Consequently, the most satisfactory LED performance was observed in a structure with relatively lower growth temperature of prestrained layers that exhibited larger V-pits, leading to higher strain relaxation and thinner n-type GaN layers, which prevent light absorption caused by n-type GaN layers.

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3D numerical modeling of the carrier transport and radiative efficiency for InGaN/GaN light emitting diodes with V-shaped pits

Cited by 42 publications

References 36 publications

Localization landscape theory of disorder in semiconductors. III. Application to carrier transport and recombination in light emitting diodes

Localization landscape theory of disorder in semiconductors. III. Application to carrier transport and recombination in light emitting diodes

Three dimensional characterization of GaN-based light emitting diode grown on patterned sapphire substrate by confocal Raman and photoluminescence spectromicroscopy

Effect of Strains and V-Shaped Pit Structures on the Performance of GaN-Based Light-Emitting Diodes

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