• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.251-254
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• 2012

In this paper, the output characteristics of GaN-based LED considering quantum well structure are analyzed. The basic structure of the LED consists of active region of GaN barrier and InGaN quantum well between AlGaN EBL(Electron Blocking Layer) and AlGaN HBL(Hole Blocking Layer) on GaN buffer layer. The output power, internal quantum efficiency characteristics of LED active region considering thickness of quantum well, number of quantum well and doping of barrier are analyzed using ISE-TCAD.

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.05a
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• pp.21.2-21.2
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• 2007

• Applied Science and Convergence Technology
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• v.26 no.3
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• pp.52-54
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• 2017

An InGaN/GaN multiple quantum well (MQW) structure is grown on a GaN/sapphire template using a plasma-assisted molecular beam epitaxy (PA-MBE). The fluctuation of the quantum well thickness formed from roughly-grown InGaN layer results in a disordered photoluminescence (PL) spectrum. The surface morphologies of the InGaN layers with various In compositions are investigated by reflection high energy electron diffraction (RHEED) and atomic force microscopy (AFM). A blurred InGaN/GaN hetero-interface and the non-uniform QW size is confirmed by high resolution transmission electron microscopy (HR-TEM). Inhomogeneity of the quantum confinement results in a degradation of the quantum efficiency even though the InGaN layer has a uniform In composition.

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.509-510
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• 2009

The optical gain of InGaN/GaN multi quantum well (MQW) resonant-cavity light-emitting diode (RC-LED) with different Indium composition and well width in the multi-quantum well was investigated. The optimized optical gain was obtained by simulating active region InGaN/GaN with some test values of well width and Indium composition. By simulation tool, we could simulate on several cases, and then we got exact well width and Indium composition that makes optical gain maximum due to the short wavelength of 470 nm for blue light emission.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.3
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• pp.1-5
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• 2018

In this study, the effects of indium (In) doping in InGaN/GaN multi quantum well (MQW) on photoelectrochemical (PEC) properties were investigated. Each quantum well (QW) layer with controlled In content were grown on sapphire substrate. Before growth of MQW, GaN growth consisted of various stages in the following order: buffer GaN growth, undoped GaN growth, and Si-doped n-type GaN growth. Absorbance of InGaN/GaN MQW having different In composition was higher than that of the InGaN/GaN MQW having a constant In composition. It indicates that InGaN layer having different In composition absorbs light having a broad spectrum energy. These results are in agreement with those in photoluminescence (PL). After evaluation of PEC properties, it demonstrated that InGaN/GaN MQW having different In composition was improved InGaN/GaN MQW having constant In composition in PEC water splitting ability.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.08a
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• pp.121-125
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• 2003

Time-resolved photoluminescence from InGaN/GaN multi-quantum well structures was investigated for two different shapes of square- and trapezoidal wells grown by metal-organic chemical vapor deposition. To compare to the conventional square well structure with a radiative recombination lifetime of 0.170 nsec, the large value of lifetime of 0.540 nsec from trapezoidal well were found at room temperature. This value is similar to the value for GaN host material indicating no confinement effect of quantum well. Furthermore, the high resolution transmission electron microscopy image provides the In clustering effect in the trapezoidal well structure.

• Transactions on Electrical and Electronic Materials
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• v.4 no.5
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• pp.19-23
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• 2003

Time-resolved photoluminescence from InGaN/GaN multi-quantum well structures was investigated for two different shapes of square-and trapezoidal wells grown by metal-organic chemical vapor deposition. To compare to the conventional square well structure with a radiative recombination lifetime of 0.170 nsec, the large value of lifetime of 0.540 nsec from trapezoidal well were found at room temperature. This value is similar to the value for GaN host material indicating no confinement effect of quantum well. Furthermore, the high resolution transmission electron microscopy image provides the In clustering effect in the trapezoidal well structure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.52-54
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• 2008

The authors investigated the InGaN/GaN multi-quantum well blue light emitting diodes with the implements of the photonic crystals fabricated at the top surface of p-GaN layer or the bottom interface of n-GaN layer. The top photonic crystals result in the lattice-dependent photoluminescence spectra for the blue light emitting diodes, which have a wavelength of 450nm. However, the bottom photonic crystal shows a big shift of the photoluminescence peak from 444 nm to 504 nm and played as a role of quality enhancement for the crystal growth of GaN thin film. The micro-Raman spectroscopy shows the improved epitaxial quality of GaN thin film.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.686-689
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• 2012

In this paper, the GaN-based LED characteristics are analyzed using ISE-TCAD. The LED consists of GaN barriers, active region of InGaN quantum well, AlGaN EBL(Electron Blocking Layer) and AlGaN HBL(Hole Blocking Layer) on GaN buffer layer. The output power characteristics of LED considering Auger recombination rate, thickness of quantum well and number of quantum wells are analyzed and some criteria for the design of LED are proposed.

• Journal of the Korean Vacuum Society
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• v.16 no.1
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• pp.27-32
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• 2007

We have investigated photoluminescence(PL) spectra of four $In_xGa_{1-x}N(x=0.15)/GaN$ multiple quantum well(MQW) structures with different well widths in order to study a phenomenon on crystal phase separation. The asymmetic behavior of PL spectra becomes stronger with increase of the well width from 1.5 nm to 6.0 nm, which indicates dual-peak nature. Analyzing the dual-peak fit PL spectra, we have observed that the intensity of low-energy shoulder peak rapidly becomes stronger, compared to that of high-energy peak corresponding to a transition in InGaN QW. It suggests that InGaN QW has two phases with tiny different In compositions, and that In-rich(InN-like) phase forms more and more relatively than stoichiometric InGaN(x=0.15) phase by the InN phase separation mechanism as the QW width increases. PL spectrum of 6.0-nm sample shows an additional peak at low-energy lesion(${\sim}2.0\;eV$) whose energy position is almost the same as a defect band of yellow luminescence frequently observed in GaN epilayers. It may be due to a defect resulted from In deficiency formed with development of the phase separation.