Improved crystal quality of non-polar <i>a</i>-plane GaN epi-layers directly grown on optimized hole-array patterned <i>r</i>-sapphire substrates

Wang, Caiwei; Jiang, Yang; Die, Junhui; Shen, Yan; Hu, Xueyuan; Hu, W.; Ma, Zhuangzhuang; Deng, Zhen; Jia, Haiqiang; Chen, Hong

doi:10.1039/c8ce01988f

Cited by 8 publications

(5 citation statements)

References 34 publications

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“…The XRC ω-scan was performed at phi angle intervals of 30°, where the X-ray beam was placed parallel to the c - and m -axes along the (11–20) plane at 0° and 90° phi angles, respectively. The FWHM plot exhibits the same trend as the nonpolar XRC measurements, that is, the anisotropy of nonpolar GaN results in an “M”-shaped plot with respect to the phi angle 10 , 15 , 31 . The lowest FWHMs are observed at a phi angle of 0°, corresponding to 1224, 1044, 864 and 756 arcsec for samples S1, S2, S3 and S4, respectively.…”

Section: Resultsmentioning

confidence: 53%

“…Note that the anisotropy of nonpolar GaN induces orthorhombic distortion in the grown a -GaN 11 , 15 , 34 . The asymmetric crystal arrangement consequently distorts the wurtzite structure 18 .…”

Section: Resultsmentioning

confidence: 99%

“…This phenomenon promotes defects and increases the densities of dislocations, such as BSFs and TDs, leading to challenges in determining the lattice parameters, because more variables need to be considered 11 – 14 . Several strategies have recently been developed to overcome this challenge, including patterning of hole arrays, patterning of stripped SiO 2 and regrowth on Ni nanopatterned a -GaN templates 15 – 17 . However, these techniques are time-consuming because other processes (ex situ) are required to supplement the epitaxial process.…”

Section: Introductionmentioning

confidence: 99%

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Impact of sandwiched strain periodic multilayer AlN/GaN on strain and crystalline quality of a-plane GaN

Kamarundzaman

Shuhaimi

Azman

et al. 2021

Sci Rep

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We demonstrated high-quality single crystalline a-plane undoped-gallium nitride grown on a nonpatterned r-plane sapphire substrate via metal–organic chemical vapor deposition. The effect of four different numbers of sandwiched strain-periodic AlN/GaN multilayers on the strain state, crystal quality, optical and electrical properties was investigated. Field emission scanning electron microscopy and atomic force microscopy showed that the surface morphology was improved upon insertion of 120 pairs of AlN/GaN thin layers with a root-mean-square roughness of 2.15 nm. On-axis X-ray ω-scan rocking curves showed enhanced crystalline quality: the full width at half maximum decreased from 1224 to 756 arcsec along the [0001] direction and from 2628 to 1360 arcsec along the [1–100] direction for a-GaN grown with 120 pairs of AlN/GaN compared to a-GaN without AlN/GaN pairs. Reciprocal space mapping showed that a-plane GaN with a high number of AlN/GaN pairs exhibits near-relaxation strain states. Room-temperature photoluminescence spectra showed that the sample with the highest number of AlN/GaN pairs exhibited the lowest-intensity yellow and blue luminescence bands, indicating a reduction in defects and dislocations. The a-plane InGaN/GaN LEDs with 120 pairs of SSPM-L AlN/GaN exhibited a significant increase (~ 250%) in light output power compared to that of LEDs without SSPM-L AlN/GaN pairs.

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Section: Resultsmentioning

confidence: 53%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Impact of sandwiched strain periodic multilayer AlN/GaN on strain and crystalline quality of a-plane GaN

Kamarundzaman

Shuhaimi

Azman

et al. 2021

Sci Rep

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“…This minimum BSFD is quite remarkable compared to that currently reported for m-plane AlN and a-plane GaN (BSFD ∼ 5000 cm −1 ). 11,26 The representative works on nonpolar AlN fabricated on the sapphire substrates are listed in Table 2, in which the FWHMs and BSFDs are used to reflect the crystal quality of the nonpolar AlN samples.…”

Section: Resultsmentioning

confidence: 99%

The stacking fault annihilation in a-plane AlN during high-temperature annealing

et al. 2023

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“…Recently, (1120)-plane nonpolar GaN film was successfully grown on a (0001)-plane sapphire substrate using pulsed laser deposition (PLD) technology [36]. It was reported that the crystalline quality of nonpolar GaN could be improved by introducing a patterned SiO 2 layer [37]. However, the introduction of secondary epitaxy processes or growth techniques that are not entirely based on the metal organic chemical vapor deposition (MOCVD) system is detrimental to commercialization.…”

Section: Introductionmentioning

confidence: 99%

Effects of Buffer Layer on Structural Properties of Nonpolar (112¯0)-Plane GaN Film

Zhao

Suo

et al. 2023

Crystals

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Nonpolar (112¯0) a-plane GaN films were grown on semipolar (11¯02) r-plane sapphire substrates using various buffer layers within a low-pressure metal organic chemical vapor deposition system. The structural properties of nonpolar a-plane GaN films were intensively investigated by X-ray diffraction and Raman spectra measurements. A set of buffer layers were adopted from a GaN layer to a composite layer containing a multiple AlN layers and a gradually varied-Al-content AlGaN layer, the full width at half maximum of the X-ray rocking curves measured along the [0001] and [101¯0] directions of a-plane GaN were reduced by 35% and 37%, respectively. It was also found that the basal-plane stacking faults (BSFs) density can be effectively reduced by the heterogeneous interface introduced together with the composite buffer layer. An order of magnitude reduction in BSFs density, as low as 2.95 × 104 cm−1, and a pit-free surface morphology were achieved for the a-plane GaN film grown with the composite buffer layer, which is promising for the development of nonpolar GaN-based devices in the future.

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Improved crystal quality of non-polar a-plane GaN epi-layers directly grown on optimized hole-array patterned r-sapphire substrates

Abstract: The characteristics of a-plane GaN films directly grown on silicon dioxide (SiO2) hole-array patterned r-sapphire substrates (HPSS) were investigated in this work.

Cited by 8 publications

References 34 publications

Impact of sandwiched strain periodic multilayer AlN/GaN on strain and crystalline quality of a-plane GaN

Impact of sandwiched strain periodic multilayer AlN/GaN on strain and crystalline quality of a-plane GaN

The stacking fault annihilation in a-plane AlN during high-temperature annealing

Effects of Buffer Layer on Structural Properties of Nonpolar (112¯0)-Plane GaN Film

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