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Article
Open AccessPublisher Correction: Impact of alloy fluctuations and Coulomb effects on the electronic and optical properties of c-plane GaN/AlGaN quantum wells
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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Article
Open AccessImpact of alloy fluctuations and Coulomb effects on the electronic and optical properties of c-plane GaN/AlGaN quantum wells
We report on a combined theoretical and experimental study of the impact of alloy fluctuations and Coulomb effects on the electronic and optical properties of \(c\)c-plane GaN/AlGaN multi-quantum well systems. Th...
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Article
Open AccessHysteretic photochromic switching of Eu-Mg defects in GaN links the shallow transient and deep ground states of the Mg acceptor
Although p-type activation of GaN by Mg underpins a mature commercial technology, the nature of the Mg acceptor in GaN is still controversial. Here, we use implanted Eu as a ‘spectator ion’ to probe the lattic...
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Article
The Use of Spatial Analysis Techniques in Defect and Nanostructure Studies
Spatial analysis techniques were used to investigate defects and nanostructures in the III-nitride system. Dislocations in GaN films were distributed nonrandomly, forming both short-scale and large-scale linea...
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Article
The origin and reduction of dislocations in Gallium Nitride
Two methods for GaN growth on sapphire by metal-organic vapour phase epitaxy are discussed. The first involves only two-dimensional (2D) growth, and results in a high dislocation density, but also a high elect...
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Chapter and Conference Paper
The atomic structure of GaN-based quantum wells and interfaces
We have used a combination of high resolution electron microscopy (HREM), three dimensional atom probe (3DAP) microscopy and atomic force microscopy (AFM) to reveal the atomic structure of InGaN quantum wells ...
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Chapter and Conference Paper
Characterisation of InxAl1-xN Epilayers Grown on GaN
InxAl1-xN epilayers were grown on GaN pseudo-substrates at a range of temperatures between 900 °C and 750 °C. Indium incorporation decreased as the growth temperature was increased, and surface roughness at the 1...
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Chapter and Conference Paper
Compositional and Morphological Variation in GaN/AlN/AlGaN Heterostructures
AlGaN/GaN heterostructures are an important materials system for the development of optoelectronic devices emitting in the ultraviolet region of the electromagnetic spectrum. Due to a difference in lattice par...
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Chapter and Conference Paper
Calibration and Applications of Scanning Capacitance Microscopy: n-Type GaN
To understand the basic mechanisms of scanning capacitance microscopy (SCM) four GaN-based test structures were grown on sapphire. These have been designed to test the carrier concentration and spatial detecti...
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Chapter and Conference Paper
The Puzzle of Exciton Localisation in GaN-Based Structures: TEM, AFM and 3D APFIM Hold the Key
The InGaN/GaN quantum well system emits intense light even though the dislocation density is high. This is a puzzle since dislocations should quench the light emission. Photoluminescence (PL) experiments show ...
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Chapter and Conference Paper
Strain Relaxation in an AlGaN/GaN Quantum Well System
AlGaN/GaN quantum well stacks have been grown in a series with 10.5nm Al0.5Ga0.5N barriers and 1.5nm, 2.5nm and 3.5nm GaN wells. These samples have been studied by weak beam dark field (WBDF) TEM. Threading dislo...
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Chapter and Conference Paper
The Effect of Silane Treatment of AlxGa1−xN Surfaces
AlxGa1−xN epilayers grown by metal-organic vapour-phase epitaxy have been treated in situ, post-growth with silane and ammonia with the aim of increasing the size of the surface pits relating to threading disloca...
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Article
The impact of electron beam damage on the detection of indium-rich localisation centres in InGaN quantum wells using transmission electron microscopy
High-resolution transmission electron microscope (HRTEM) lattice fringe images and lattice parameter maps are used to reveal the rapid modification of InGaN quantum wells by the electron beam in a TEM. Images ...
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Chapter and Conference Paper
Stranski-Krastanov growth for InGaN/GaN: wetting layer thickness changes
We have investigated InGaN nanostructures grown by atmospheric pressure metal-organic vapour phase epitaxy. The variation of the 3D nanostructure density and the wetting layer thickness with growth time have b...
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Chapter and Conference Paper
Reduction of threading dislocation density using in-situ SiNx interlayers
In-situ SiNx interlayers (ILs) have been used in order to reduce the density of threading dislocations (TDs) in MOVPE grown GaN and the mechanisms of TD reduction have been investigated by transmission electron m...
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Chapter and Conference Paper
In GaN-GaN quantum wells: their luminescent and nano-structural properties
The luminescent and nano-structural properties of InGaN-GaN quantum wells have been investigated as a function of indium content. Photoluminescence spectra of single quantum wells show an excitonic emission me...
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Chapter and Conference Paper
A TEM Study of A1N Interlayer Defects in AlGaN/GaN Heterostructures
A series of Al0.47Ga0.53N/GaN heterostructures with a range of different AlN interlayer thicknesses has been examined. We find that when the interlayer thickness is greater than ∼5nm, it becomes possible to grow ...
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Article
Reduction of Threading Dislocations in GaN grown on 'c' plane sapphire by Movpe
The reduction of threading dislocations (TDs) in GaN is very important as TDs act as non-radiative recombination centres and generally reduce the luminescence efficiency of GaN-based optoelectronic devices, pa...
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Article
Growth of Uncracked Al0.80Ga0.20N/GaN DBR on Si(111)
The strain in Al0.80Ga0.20N/GaN distributed Bragg reflectors (DBRs) grown by metalorganic vapour phase epitaxy (MOVPE) on Si(111) was studied using high resolution X-ray diffraction (XRD). Previous studies have s...
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Article
Analysis of InGaN-GaN quantum well chemistry and interfaces by transmission electron microscopy and X-ray scattering
We have studied the distribution of indium in Inx Ga1-x N single quantum wells (SQWs) with compositions of In0.18Ga0.82N and In0.22Ga0.78N. Based on lattice parameter maps extracted from HRTEM lattice fringe imag...
