X-ray diffraction study on an InGaN∕GaN quantum-well structure of prestrained growth

Shiao, Wen-Yu; Huang, Chi‐Feng; Tang, Tsung-Yi; Huang, Jeng-Jie; Lu, Yen-Cheng; Chen, Cheng‐Yen; Chen, Yung‐Sheng; Yang, C. C.

doi:10.1063/1.2736860

Cited by 17 publications

(10 citation statements)

References 22 publications

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“…Several methods have been proposed to reduce the strain-induced piezoelectric field in nitride-based QWs. The strain reduction has been performed by growing a p-InGaN layer on top of the active region 7 or a QW with a composi-tionally graded barrier layer, 8 or by inserting a prestrain layer prior to the growth of QWs, 9,10 or by decreasing the QW thickness. 11 An alternative approach to circumvent the generation of an internal field is to perform growth on nonpolar and semipolar planes.…”

Section: Introductionmentioning

confidence: 99%

Strain relaxation effect by nanotexturing InGaN/GaN multiple quantum well

Ramesh¹,

Kikuchi²,

Kishino³

et al. 2010

Journal of Applied Physics

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The relaxation of lattice-mismatched strain by deep postetching was systematically investigated for InGaN/GaN multiple quantum wells ͑MQWs͒. A planar heterojunction wafer, which included an In 0.21 Ga 0.79 N ͑3.2 nm͒/GaN ͑14.8 nm͒ MQW, was etched by inductively coupled plasma dry etching, to fabricate high-density nanopillar, nanostripe, and nanohole arrays. The etching depth was 570 nm for all nanostructures. The diameter of the nanopillars was varied from 50 to 300 nm, then the mesa stripe width of the nanostripes and the diameter of the nanoholes were varied from 100 nm to 440 nm and 50 nm to 310 nm, respectively. The effect of strain relaxation on various optical properties was investigated. For example, in an array of nanopillars with diameter 130 nm and interval 250 nm, a large blueshift in the photoluminescence ͑PL͒ emission peak from 510 nm ͑as-grown͒ to 459 nm occurred at room temperature ͑RT͒. PL internal quantum efficiency ͑defined by the ratio of PL integral intensity at 300 K to that at 4.2 K͒ was enhanced from 34% ͑as-grown͒ to 60%, and the PL decay time at 4.2 K was reduced from 22 ns ͑as-grown͒ to 4.2 ns. These results clearly indicate the reduction of lattice-mismatched strain by postetching, which enhanced strain reduction with decreasing nanopillar diameter down to a diameter of 130 nm, where the strain reduction became saturated. The dependence of RT-PL decay time on nanopillar diameter was measured, and the surface nonradiative recombination velocity was estimated to be 5.8 ϫ 10 2 cm/ s. This relatively slow rate indicates a little etching damage.

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Section: Introductionmentioning

confidence: 99%

Strain relaxation effect by nanotexturing InGaN/GaN multiple quantum well

Ramesh¹,

Kikuchi²,

Kishino³

et al. 2010

Journal of Applied Physics

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“…Furthermore, the lattice parameters of n-GaN and InGaN in MQWs are estimated to be: a GaN = 0.3190 nm, c GaN = 0.5186 nm; a InGaN = 0.3194 nm, c InGaN = 0.5286 nm. Obviously, the layer relaxation value (R) of InGaN/GaN is estimated to be R InGaN = 10.9% and R GaN = 89.1%, respectively3839.…”

mentioning

confidence: 99%

Highly-efficient GaN-based light-emitting diode wafers on La0.3Sr1.7AlTaO6 substrates

Wang

Yang

Gao

et al. 2015

Sci Rep

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Highly-efficient GaN-based light-emitting diode (LED) wafers have been grown on La0.3Sr1.7AlTaO6 (LSAT) substrates by radio-frequency molecular beam epitaxy (RF-MBE) with optimized growth conditions. The structural properties, surface morphologies, and optoelectronic properties of as-prepared GaN-based LED wafers on LSAT substrates have been characterized in detail. The characterizations have revealed that the full-width at half-maximums (FWHMs) for X-ray rocking curves of GaN(0002) and GaN(10-12) are 190.1 and 210.2 arcsec, respectively, indicating that high crystalline quality GaN films have been obtained. The scanning electron microscopy and atomic force microscopy measurements have shown the very smooth p-GaN surface with the surface root-mean-square (RMS) roughness of 1.3 nm. The measurements of low-temperature and room-temperature photoluminescence help to calculate the internal quantum efficiency of 79.0%. The as-grown GaN-based LED wafers have been made into LED chips with the size of 300 × 300 μm2 by the standard process. The forward voltage, the light output power and the external quantum efficiency for LED chips are 19.6 W, 2.78 V, and 40.2%, respectively, at a current of 20 mA. These results reveal the high optoelectronic properties of GaN-based LEDs on LSAT substrates. This work brings up a broad future application of GaN-based devices.

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“…This large lattice mismatch leads to strong compressive strain in the main QWs, which can result in the generation of defects, dislocations and alloy nonhomogeneity [15]. Here, the bottom low indium-content blue QWs may play another beneficial role in partial strain relaxation, thus functioning to optimize the strain distribution and improve the crystal quality of the main QWs [26].…”

Section: Led Wafer Epitaxial Growth and Device Fabricationmentioning

confidence: 99%

Hole transport assisted by the piezoelectric field in In0.4Ga0.6N/GaN quantum wells under electrical injection

Zhang

Xie

Yan

et al. 2015

Journal of Applied Physics

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The authors observe the significant penetration of electrically injected holes through InGaN/GaN quantum wells (QWs) with an indium mole fraction of 40%. This effect and its current density dependence were analysed by studies on micro-pixel light-emitting diodes, which allowed current densities to be varied over a wide range up to 5 kA/cm2. The systematic changes in electroluminescence spectra are discussed in the light of the piezoelectric field in the high-indium-content QWs and its screening by the carriers. Simulations were also carried out to clarify the unusual hole transport mechanism and the underlying physics in these high-indium QWs

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X-ray diffraction study on an InGaN∕GaN quantum-well structure of prestrained growth

Cited by 17 publications

References 22 publications

Strain relaxation effect by nanotexturing InGaN/GaN multiple quantum well

Strain relaxation effect by nanotexturing InGaN/GaN multiple quantum well

Highly-efficient GaN-based light-emitting diode wafers on La0.3Sr1.7AlTaO6 substrates

Hole transport assisted by the piezoelectric field in In0.4Ga0.6N/GaN quantum wells under electrical injection

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