Defect Reduction in Semi-Polar (112̄2) Gallium Nitride Grown Using Epitaxial Lateral Overgrowth

Zhu, Tongtong; Sutherland, Danny; Badcock, T. J.; Hao, Rui; Moram, M. A.; Dawson, Philip E.; Kappers, Menno J.; Oliver, Rachel A.

doi:10.7567/jjap.52.08jb01

Cited by 9 publications

(11 citation statements)

References 27 publications

(35 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The BSFs were on average shorter than 2

μ

m due to the ragged coalescence region. The BSF density was always

<

500 cm

^{- 1}

which is similar to reports in literature using patterned substrates , and at least a magnitude smaller than what was reported for ELOG .…”

Section: Resultssupporting

confidence: 88%

See 1 more Smart Citation

Low defect large area semi‐polar (112) GaN grown on patterned (113) silicon

Pristovsek

Han

Zhu

et al. 2014

Physica Status Solidi (b)

Self Cite

View full text Add to dashboard Cite

We report on the growth of semi-polar GaN (112) templates on patterned Si (113) substrates. Trenches were etched in Si (113) using KOH to expose Si {111} sidewalls. Subsequently an AlN layer to prevent meltback etching, an AlGaN layer for stress management, and finally two GaN layers were deposited. Total thicknesses up to 5 m were realised without cracks in the layer. Transmission electron microscopy showed that most dislocations propagate along [0001] direction and hence can be covered by overgrowth from the next trench. The defect densities were below and stacking fault densities less than 100 cm . These numbers are similar to reports on patterned r-plane sapphire. Typical X-ray full width at half maximum (FHWM) were 500” for the asymmetric (00.6) and 450” for the (11.2) reflection. These FHWMs were 50 % broader than reported for patterned r-plane sapphire which is attributed to different defect structures and total thicknesses. The surface roughness shows strong variation on templates. For the final surface roughness the roughness of the sidewalls of the GaN ridges at the time of coalescence are critical.

show abstract

“…The BSFs were on average shorter than 2

μ

m due to the ragged coalescence region. The BSF density was always

<

500 cm

^{- 1}

which is similar to reports in literature using patterned substrates , and at least a magnitude smaller than what was reported for ELOG .…”

Section: Resultssupporting

confidence: 88%

“…Still these do not reduce BSFs below

10^{5}

^{- 1}

. A reduction in BSF was obtained by two step growth with epitaxial lateral overgrowth (ELOG) . A related approach of regrowth of patterned nanowires is currently even commercialised.…”

Section: Introductionmentioning

confidence: 99%

Low defect large area semi‐polar (112) GaN grown on patterned (113) silicon

Pristovsek

Han

Zhu

et al. 2014

Physica Status Solidi (b)

Self Cite

View full text Add to dashboard Cite

show abstract

“…[7][8][9] Both planar and patterned substrates have been used to achieve semi-polar growth, and these different growth techniques have an impact on the chevron formation. 10,11 For growth on planar substrates, the formation of chevrons has been attributed to interference between undulations along the ½11 2 3 and ½1 100 directions, which in turn occur due to anisotropic surface diffusion. 12 For samples grown using epitaxial lateral overgrowth (ELOG) methods, where a patterned substrate or template is used, there is an additional effect causing the chevrons to appear more pronounced.…”

Section: Introductionmentioning

confidence: 99%

Cathodoluminescence studies of chevron features in semi-polar (112¯2) InGaN/GaN multiple quantum well structures

Brasser

Bruckbauer

Gong

et al. 2018

Journal of Applied Physics

View full text Add to dashboard Cite

This version is available at https://strathprints.strath.ac.uk/63662/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the Strathprints administrator: strathprints@strath.ac.ukThe Strathprints institutional repository (https://strathprints.strath.ac.uk) is a digital archive of University of Strathclyde research outputs. It has been developed to disseminate open access research outputs, expose data about those outputs, and enable the management and persistent access to Strathclyde's intellectual output. Epitaxial overgrowth of semi-polar III-nitride layers and devices often leads to arrowhead-shaped surface features, referred to as chevrons. We report on a study into the optical, structural, and electrical properties of these features occurring in two very different semi-polar structures, a blueemitting multiple quantum well structure, and an amber-emitting light-emitting diode. Cathodoluminescence (CL) hyperspectral imaging has highlighted shifts in their emission energy, occurring in the region of the chevron. These variations are due to different semi-polar planes introduced in the chevron arms resulting in a lack of uniformity in the InN incorporation across samples, and the disruption of the structure which could cause a narrowing of the quantum wells (QWs) in this region. Atomic force microscopy has revealed that chevrons can penetrate over 150 nm into the sample and quench light emission from the active layers. The dominance of non-radiative recombination in the chevron region was exposed by simultaneous measurement of CL and the electron beam-induced current. Overall, these results provide an overview of the nature and impact of chevrons on the luminescence of semi-polar devices.

show abstract

“…The sample with the largest content of x = 0.56 even exhibits pits at the tips of some of the chevrons. Chevrons have already been reported for semi-polar nitride structures, which have been grown using an overgrowth technique 15 , 24 – 28 . These chevrons are already present in the semi-polar GaN templates which were used for the growth of the AlGaN 29 .…”

Section: Resultsmentioning

confidence: 99%

Spatially-resolved optical and structural properties of semi-polar $$\mathrm{(11}\bar{2}\mathrm{2)}$$ Al x Ga1−x N with x up to 0.56

Bruckbauer

Naresh-Kumar

et al. 2017

Sci Rep

View full text Add to dashboard Cite

Pushing the emission wavelength of efficient ultraviolet (UV) emitters further into the deep-UV requires material with high crystal quality, while also reducing the detrimental effects of built-in electric fields. Crack-free semi-polar AlxGa1−xN epilayers with AlN contents up to x = 0.56 and high crystal quality were achieved using an overgrowth method employing GaN microrods on m-sapphire. Two dominant emission peaks were identified using cathodoluminescence hyperspectral imaging. The longer wavelength peak originates near and around chevron-shaped features, whose density is greatly increased for higher contents. The emission from the majority of the surface is dominated by the shorter wavelength peak, influenced by the presence of basal-plane stacking faults (BSFs). Due to the overgrowth technique BSFs are bunched up in parallel stripes where the lower wavelength peak is broadened and hence appears slightly redshifted compared with the higher quality regions in-between. Additionally, the density of threading dislocations in these region is one order of magnitude lower compared with areas affected by BSFs as ascertained by electron channelling contrast imaging. Overall, the luminescence properties of semi-polar AlGaN epilayers are strongly influenced by the overgrowth method, which shows that reducing the density of extended defects improves the optical performance of high AlN content AlGaN structures.

show abstract

Defect Reduction in Semi-Polar (112̄2) Gallium Nitride Grown Using Epitaxial Lateral Overgrowth

Cited by 9 publications

References 27 publications

Low defect large area semi‐polar (112) GaN grown on patterned (113) silicon

Low defect large area semi‐polar (112) GaN grown on patterned (113) silicon

Cathodoluminescence studies of chevron features in semi-polar (112¯2) InGaN/GaN multiple quantum well structures

Spatially-resolved optical and structural properties of semi-polar $$\mathrm{(11}\bar{2}\mathrm{2)}$$ Al x Ga1−x N with x up to 0.56

Contact Info

Product

Resources

About