P. R. Edwards
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View article: Hyperspectral alignment capability for direct writing systems enabled by structured illumination with a micro-LED array
Hyperspectral alignment capability for direct writing systems enabled by structured illumination with a micro-LED array Open
Direct writing systems equipped with a confocal micro-light-emitting diode array can employ active illumination for alignment purposes. Based on the principles of single-pixel imaging, structured illumination can be used to obtain position…
View article: Molecular beam epitaxy of boron arsenide layers
Molecular beam epitaxy of boron arsenide layers Open
Thermal management is the main technological challenge for next generation electronic devices. Recently, several groups successfully demonstrated boron arsenide (BAs) microcrystals with an ultrahigh thermal conductivity approaching that of…
View article: Comparative Study of the Optical Properties of α‐, β‐, and κ‐Ga<sub>2</sub>O<sub>3</sub>
Comparative Study of the Optical Properties of α‐, β‐, and κ‐Ga<sub>2</sub>O<sub>3</sub> Open
A systematic investigation of the optical properties of β‐, α‐, and κ‐phase gallium oxide (Ga 2 O 3 ) polymorphs is conducted by UV–vis spectrophotometry through the Swanepoel method and temperature‐dependent photoluminescence. Using the s…
View article: Impact of phase signal formulations on tilt-to-length coupling noise in the LISA test mass interferometer
Impact of phase signal formulations on tilt-to-length coupling noise in the LISA test mass interferometer Open
Tilt-to-length (TTL) coupling in the Laser Interferometer Space Antenna (LISA) can generate spurious displacement noise that potentially affects the measurement of gravitational wave signals. In each test mass interferometer, the coupling …
View article: Role of the electron transport layer in dictating the nanoscale heterogeneity in all-inorganic perovskite absorbers – correlating the optoelectronic and crystallographic properties
Role of the electron transport layer in dictating the nanoscale heterogeneity in all-inorganic perovskite absorbers – correlating the optoelectronic and crystallographic properties Open
The impact of underlying electron transport layer (SnO 2 , TiO 2 and ZnO) on the optoelectronic and structural properties of the CsPbI 2 Br perovskite overlayer is explored using Cathodoluminescence (CL) and Electron Back Scatter Diffracti…
View article: Recycling self-assembled colloidal quantum dot supraparticle lasers
Recycling self-assembled colloidal quantum dot supraparticle lasers Open
Supraparticles comprising semiconductor colloidal quantum dots as building blocks are a new class of microscopic lasers with a wide host of applications, including photocatalysis, biological and environmental sensing, integrated photonics,…
View article: Luminescence properties of dislocations in α-Ga<sub>2</sub>O<sub>3</sub>
Luminescence properties of dislocations in α-Ga<sub>2</sub>O<sub>3</sub> Open
Dislocations in epitaxial lateral overgrown α -Ga 2 O 3 are investigated using hyperspectral cathodoluminescence spectroscopy. The dislocations are associated with a reduction of self-trapped hole-related luminescence ( ca. 3.6 eV line) wh…
View article: Colloidal Semiconductor Quantum Well Supraparticles as Low‐Threshold and Photostable Microlasers
Colloidal Semiconductor Quantum Well Supraparticles as Low‐Threshold and Photostable Microlasers Open
This study introduces and compares the lasing performance of micron‐sized and sphere‐shaped supraparticle (SP) lasers fabricated through bottom‐up assembly of II‐VI semiconductor colloidal quantum wells (CQWs) with their counterparts made …
View article: Simultaneous mapping of cathodoluminescence spectra and backscatter diffraction patterns in a scanning electron microscope
Simultaneous mapping of cathodoluminescence spectra and backscatter diffraction patterns in a scanning electron microscope Open
Electron backscatter diffraction and cathodoluminescence are complementary scanning electron microscopy modes widely used in the characterisation of semiconductor films, respectively revealing the strain state of a crystalline material and…
View article: Tin Gallium Oxide Epilayers on Different Substrates: Optical and Compositional Analysis
Tin Gallium Oxide Epilayers on Different Substrates: Optical and Compositional Analysis Open
Electron beam techniques have been used to analyze the impact of substrate choice and growth parameters on the compositional and optical properties of tin gallium oxide [(Sn x Ga 1− x ) 2 O 3 ] thin films grown by plasma‐assisted molecular…
View article: Biotinylated Photocleavable Semiconductor Colloidal Quantum Dot Supraparticle Microlaser
Biotinylated Photocleavable Semiconductor Colloidal Quantum Dot Supraparticle Microlaser Open
Luminescent supraparticles of colloidal semiconductor nanocrystals can act as microscopic lasers and are hugely attractive for biosensing, imaging, and drug delivery. However, biointerfacing these to increase functionality while retaining …
View article: Unravelling the chloride dopant induced film improvement in all-inorganic perovskite absorbers
Unravelling the chloride dopant induced film improvement in all-inorganic perovskite absorbers Open
Cl − anions remain in the CsPbI 2 Br film after annealing directing the preferential crystal orientation of the films along [100].
View article: Synthesis of Plasmonically Active Titanium Nitride Using a Metallic Alloy Buffer Layer Strategy
Synthesis of Plasmonically Active Titanium Nitride Using a Metallic Alloy Buffer Layer Strategy Open
Titanium nitride (TiN) has emerged as a highly promising alternative to traditional plasmonic materials. This study focuses on the inclusion of a Cr90Ru10 buffer layer between the substrate and thin TiN film, which en…
View article: Simultaneous Growth Strategy of High-Optical-Efficiency GaN NWs on a Wide Range of Substrates by Pulsed Laser Deposition
Simultaneous Growth Strategy of High-Optical-Efficiency GaN NWs on a Wide Range of Substrates by Pulsed Laser Deposition Open
Here, we explore a catalyst-free single-step growth strategy that results in high-quality self-assembled single-crystal vertical GaN nanowires (NWs) grown on a wide range of common and novel substrates (including GaN, Ga2O3…
View article: Waveguide-Integrated Colloidal Nanocrystal Supraparticle Lasers
Waveguide-Integrated Colloidal Nanocrystal Supraparticle Lasers Open
Supraparticle (SP) microlasers fabricated by the self-assembly of colloidal nanocrystals have great potential as coherent optical sources for integrated photonics. However, their deterministic placement for integration with other photonic …
View article: Electroluminescence hyperspectral imaging of light-emitting diodes using a liquid crystal tunable filter
Electroluminescence hyperspectral imaging of light-emitting diodes using a liquid crystal tunable filter Open
We demonstrate the use of a low-cost liquid-crystal-based wavelength-tunable filter and CMOS video camera to add hyperspectral imaging capabilities to a probe station equipped with a simple optical microscope. The resultant setup is used t…
View article: Core–Shell Nanorods as Ultraviolet Light-Emitting Diodes
Core–Shell Nanorods as Ultraviolet Light-Emitting Diodes Open
Existing barriers to efficient deep ultraviolet (UV) light-emitting diodes (LEDs) may be reduced or overcome by moving away from conventional planar growth and toward three-dimensional nanostructuring. Nanorods have the potential for enhan…
View article: Triple Halide Wide Bandgap Perovskites for Efficient Indoor Photovoltaics
Triple Halide Wide Bandgap Perovskites for Efficient Indoor Photovoltaics Open
Indoor photovoltaics are receiving tremendous attention due to the continuous development of the Internet of Things (IoT). Here we report a triple anion (TA) perovskite CH3NH3PbI2.6(BrCl)0.2 with a tailored bandgap suitable for maximizing …
View article: Crystal-Field Analysis of Photoluminescence from Orthorhombic EU Centers and Energy Transfer from Host to EU in Gan Co-Doped with Mg and EU
Crystal-Field Analysis of Photoluminescence from Orthorhombic EU Centers and Energy Transfer from Host to EU in Gan Co-Doped with Mg and EU Open
View article: Chlorine retention enables the indoor light harvesting of triple halide wide bandgap perovskites
Chlorine retention enables the indoor light harvesting of triple halide wide bandgap perovskites Open
Chlorine incorporation in triple halide perovskites reduces trap density and enhances the efficiency of indoor light harvesting.
View article: Role of defects in ultra-high gain in fast planar tin gallium oxide UV-C photodetector by MBE
Role of defects in ultra-high gain in fast planar tin gallium oxide UV-C photodetector by MBE Open
We report ultra-high responsivity of epitaxial (SnxGa1−x)2O3 (TGO) Schottky UV-C photodetectors and experimentally identified the source of gain as deep-level defects, supported by first principles calculations. Epitaxial TGO films were gr…
View article: Assessing the Impact of Secondary Fluorescence on X-Ray Microanalysis Results from Semiconductor Thin Films
Assessing the Impact of Secondary Fluorescence on X-Ray Microanalysis Results from Semiconductor Thin Films Open
The impact of secondary fluorescence on the material compositions measured by X-ray analysis for layered semiconductor thin films is assessed using simulations performed by the DTSA-II and CalcZAF software tools. Three technologically impo…
View article: The influence of threading dislocations propagating through an AlGaN UVC LED
The influence of threading dislocations propagating through an AlGaN UVC LED Open
During the epitaxy of AlGaN on sapphire for deep UV emitters, significant lattice mismatch leads to highly strained heterojunctions and the formation of threading dislocations. Combining cathodoluminescence, electron beam induced current a…
View article: Non-destructive imaging of residual strains in GaN and their effect on optical and electrical properties using correlative light–electron microscopy
Non-destructive imaging of residual strains in GaN and their effect on optical and electrical properties using correlative light–electron microscopy Open
We demonstrate a non-destructive approach to understanding the growth modes of a GaN thin film and simultaneously quantify its residual strains and their effect on optical and electrical properties using correlative scanning electron micro…
View article: Correlation between deep-level defects and functional properties of β-(Sn<i>x</i>Ga1-<i>x</i>)2O3 on Si photodetectors
Correlation between deep-level defects and functional properties of β-(Sn<i>x</i>Ga1-<i>x</i>)2O3 on Si photodetectors Open
Heterogeneous integration of β-(SnxGa1−x)2O3 (TGO) UV-C photodetectors on silicon substrates by molecular beam epitaxy is demonstrated. Multimodal electron microscopy and spectroscopy techniques reveal a direct correlation between structur…
View article: Quantification of Trace-Level Silicon Doping in Al<i><sub>x</sub></i>Ga<sub>1–<i>x</i></sub>N Films Using Wavelength-Dispersive X-Ray Microanalysis
Quantification of Trace-Level Silicon Doping in Al<i><sub>x</sub></i>Ga<sub>1–<i>x</i></sub>N Films Using Wavelength-Dispersive X-Ray Microanalysis Open
Wavelength-dispersive X-ray (WDX) spectroscopy was used to measure silicon atom concentrations in the range 35–100 ppm [corresponding to (3–9) × 10 18 cm −3 ] in doped Al x Ga 1– x N films using an electron probe microanalyser also equippe…
View article: Nanoscale Heterogeneity in CsPbBr<sub>3</sub> and CsPbBr<sub>3</sub>:KI Perovskite Films Revealed by Cathodoluminescence Hyperspectral Imaging
Nanoscale Heterogeneity in CsPbBr<sub>3</sub> and CsPbBr<sub>3</sub>:KI Perovskite Films Revealed by Cathodoluminescence Hyperspectral Imaging Open
Funding: We are grateful for funding from the EPSRC under grant code EP/L017008/1. Dr. L. K. Jagadamma acknowledges support from a Marie Skłodowska-Curie Individual Fellowship (European Commission) (MCIF: No. 745776).
View article: Progress in atomic layer deposited [alpha]-Ga2O3 materials and solar-blind detectors
Progress in atomic layer deposited [alpha]-Ga2O3 materials and solar-blind detectors Open
Atomic layer deposition (ALD) offers a low thermal budget method for producing α-Ga2O3 films on sapphire substrate. In this paper we review the recent progress on plasma-enhanced ALD growth of α-Ga2O3 and present the optical and photocondu…
View article: (Hydroxy)apatite on cement: insights into a new surface treatment
(Hydroxy)apatite on cement: insights into a new surface treatment Open
We have developed a conceptual model describing the formation and mineralisation processes of hydroxyapatite during biogenic and abiotic treatment on cement surfaces.
View article: High Figure‐of‐Merit Gallium Oxide UV Photodetector on Silicon by Molecular Beam Epitaxy: A Path toward Monolithic Integration
High Figure‐of‐Merit Gallium Oxide UV Photodetector on Silicon by Molecular Beam Epitaxy: A Path toward Monolithic Integration Open
A high figure‐of‐merit UV‐C solar‐blind photodetector (PD) fabricated from thin‐film beta‐gallium oxide (β‐Ga 2 O 3 ) grown on n ‐Si substrates by plasma‐assisted molecular beam epitaxy is demonstrated. Film growth sequences for nucleation…