Transmission electron microscopy study on pre-strained InGaN/GaN quantum wells

Chen, Yung‐Sheng; Yao, Li-Chieh; Lin, Yun; Hung, L.; Huang, Chi‐Feng; Tang, Tsung-Yi; Huang, Jih-Jeng; Shiao, Wen-Yu; Yang, C. C.

doi:10.1016/j.jcrysgro.2006.08.040

Cited by 14 publications

(9 citation statements)

References 19 publications

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“…Here, d GaN represents the lattice constant of GaN and dx stands for the calibrated local lattice size. 10 The ratio dx / d GaN describes the local relative lattice size and hence corresponds to the local indium composition, as shown in the legend of Fig. 10.…”

Section: Discussionmentioning

confidence: 99%

“…7,8 In this paper, we demonstrate the enhanced IQE of a green-emitting InGaN/GaN QW based on the prestrained growth technique. [9][10][11] In this metalorganic chemical vapor deposition ͑MOCVD͒ technique, a low-indium InGaN layer is deposited before the growth of high-indium InGaN/GaN QWs for creating a tensile strain in the GaN barrier layer right above it. The indium content and thickness of the lowindium InGaN layer need to be well adjusted such that the possibly strongest tensile strain can be generated in the GaN barrier layer.…”

Section: Introductionmentioning

confidence: 99%

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Enhanced efficiency and reduced spectral shift of green light-emitting-diode epitaxial structure with prestrained growth

Huang

Liu

et al. 2008

Journal of Applied Physics

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The enhanced emission efficiency and reduced spectral shifts of a green InGaN/GaN quantum-well (QW) light-emitting-diode epitaxial structure by using the prestrained growth technique when compared with a control sample of the same emission spectrum with conventional growth are demonstrated. By adding an ∼7%-indium InGaN/GaN QW to the structure before the growth of designated emitting high-indium QWs, the growth temperature of the emitting QWs can be raised by 30 °C while keeping about the same emission wavelength around 544 nm in photoluminescence (PL) and 525 nm in electroluminescence (EL). The internal quantum efficiency, room-temperature PL intensity, and EL intensity at the injection current of 20 mA are increased by ∼167%, ∼140%, and ∼182%, respectively. Also, the spectral blueshift range in increasing injection current in the range of 50 mA is decreased by 46%. Based on the pump-power dependent PL measurement, it is found that the quantum-confined Stark effect (QCSE) becomes weaker in the prestrained growth sample. Also, from the calibration of the Arrhenius plots, the carrier localization effect is observed to become weaker under prestrained growth. Therefore, the enhanced emission efficiency is mainly attributed to the decreased defect density and the reduced QCSE in the prestrained sample.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Enhanced efficiency and reduced spectral shift of green light-emitting-diode epitaxial structure with prestrained growth

Huang

Liu

et al. 2008

Journal of Applied Physics

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“…Although such results cannot be very accurate, they can provide us with a general trend of indium content variation. 4 Figure 5 shows two cross-section TEM images of sample D, including part ͑a͒ for illustrating the six QWs ͑indicated by arrows͒ with the low-indium one at the lower-left corner and ͑b͒ for a two-electron-beam image of the third QW from the top. Although the locations and shapes of the six QWs are well defined in the low-resolution image of Fig.…”

Section: Materials Analysismentioning

confidence: 99%

“…6͑a͒ and 6͑b͒, the average-indium content of each QW can be evaluated. 4 The average-indium contents of the sixth and third QWs in Figs. 6͑a͒ and 6͑b͒ are 7.22% and 11.28%, respectively.…”

Section: Materials Analysismentioning

confidence: 99%

“…Recently, we developed a prestrained growth technique for enhancing indium incorporation in an InGaN/GaN QW. [3][4][5] In this technique, a low-indium InGaN/GaN QW is grown before the designated light-emitting high-indium InGaN/GaN QWs to create tensile strain in the GaN barrier layer right above the low-indium QW such that the indium incorporation during the growth of the subsequent QWs becomes more effective. Hence, their indium contents can be significantly increased, leading to the efficient emissions of yellow, orange, and red colors.…”

Section: Introductionmentioning

confidence: 99%

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Dependence of spectral behavior in an InGaN/GaN quantum-well light-emitting diode on the prestrained barrier thickness

Huang

Chen

et al. 2008

Journal of Applied Physics

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The dependencies of output spectral overall redshift and current-density-induced spectral blueshift on the prestrained barrier thickness in the InGaN/GaN quantum-well light-emitting diodes ͑LEDs͒ of prestrained growth are demonstrated. Due to the stronger prestrain effect in a sample of a thinner prestrained barrier, the overall spectral redshift range increases and the current-density-induced blueshift range decreases with decreasing prestrained barrier thickness. Also, in terms of device resistance and saturation current, the LED performances of prestrained samples are superior to that of a conventional LED. With a thinner prestrained barrier, the device performance becomes better. The results are attributed to the higher average-indium content and stronger indium-rich clustering behavior in a sample of stronger prestrain. Such attributions are supported by the observations of strain state analysis in transmission electron microscopy measurements.

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Recent Progress in Long‐Wavelength InGaN Light‐Emitting Diodes from the Perspective of Epitaxial Structure

Guo

Sun

Cui

et al. 2023

Advanced Photonics Research

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Over the last decades, continuous technological advancements have been made in III‐nitride light‐emitting diodes (LEDs), so that they are considered as a promising replacement of traditional light sources. With the emission wavelength covering the entire visible spectrum, InGaN LEDs find various applications such as solid‐state lightings, full‐color displays, and visible light communication. However, the quantum efficiency of InGaN LEDs suffers from a dramatic decline as the emission wavelength extends from blue to green–red region. This issue restrains the lighting and display applications based on the color‐mixing monolithic lighting source system. In this review, the recent breakthroughs in long‐wavelength InGaN LEDs, together with the challenges and approaches to realize high‐indium‐composition InGaN epilayers, are introduced. These cover the different epitaxial substrates, nucleation layers, and epitaxial structures, especially multiple quantum wells active region. The related studies are also discussed to improve the long‐wavelength LEDs performance from the aspect of crystal quality, growth orientation, carrier‐injection, and 3D nanostructures. Finally, current status and perspectives for future long‐wavelength LEDs development are proposed briefly.

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Transmission electron microscopy study on pre-strained InGaN/GaN quantum wells

Cited by 14 publications

References 19 publications

Enhanced efficiency and reduced spectral shift of green light-emitting-diode epitaxial structure with prestrained growth

Enhanced efficiency and reduced spectral shift of green light-emitting-diode epitaxial structure with prestrained growth

Dependence of spectral behavior in an InGaN/GaN quantum-well light-emitting diode on the prestrained barrier thickness

Recent Progress in Long‐Wavelength InGaN Light‐Emitting Diodes from the Perspective of Epitaxial Structure

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