A5024359573- GaN-based semiconductor devices and materials
- ZnO doping and properties
- Diamond and Carbon-based Materials Research
- Ga2O3 and related materials
- Metal and Thin Film Mechanics
- Semiconductor Quantum Structures and Devices
- Semiconductor materials and devices
- biodegradable polymer synthesis and properties
- Advanced Cellulose Research Studies
- High-pressure geophysics and materials
- Advanced Fiber Laser Technologies
- Advanced Surface Polishing Techniques
- Microplastics and Plastic Pollution
- Electronic and Structural Properties of Oxides
- Quantum Dots Synthesis And Properties
- Advanced Materials Characterization Techniques
- Ion-surface interactions and analysis
- Nanocomposite Films for Food Packaging
- Laser-induced spectroscopy and plasma
- Additive Manufacturing and 3D Printing Technologies
- Catalysis and Hydrodesulfurization Studies
- Quantum optics and atomic interactions
- Silicon Nanostructures and Photoluminescence
- Polysaccharides and Plant Cell Walls
- Advanced Semiconductor Detectors and Materials
Shannon Applied Biotechnology Centre
2023-2024
Technological University of the Shannon: Midlands Midwest
2023-2024
University of Aveiro
1996-2005
Paderborn University
1999
Seoul National University
1999
International Superconductivity Technology Center
1999
Purdue University West Lafayette
1999
Universidad Complutense de Madrid
1993
Strain and composition distributions within wurtzite InGaN/GaN layers are investigated by high-resolution reciprocal space mapping (RSM). We illustrate the potential of RSM to detect strain gradients independently. This information is extracted from elongation broadened lattice points (RLP) in asymmetric x-ray reflections. Three InxGa1−xN/GaN (nominal x=0.25) samples with layer thickness 60, 120, 240 nm, were grown a commercial metal-organic chemical vapor deposition reactor. The RSMs around...
A depth-resolved study of the optical and structural properties wurtzite InGaN/GaN bilayers grown by metallorganic chemical vapor deposition on sapphire substrates is reported. Depth-resolved cathodoluminescence (CL) Rutherford backscattering spectrometry (RBS) were used to gain an insight into compositional profile a 75-nm thick InGaN epilayer in direction growth. CL acquired at increasing electron energies reveals peak shift about 25 meV blue when beam energy increased from 0.5...
The effect of strain on the compositional and optical properties a set epitaxial single layers InxGa1−xN was studied. Indium content measured free from effects by Rutherford backscattering spectrometry. Accurate knowledge In mole fraction, combined with x-ray diffraction measurements, allows perpendicular (εzz) to be evaluated. Optical band gaps were determined absorption spectroscopy corrected for strain. Following this approach, dependence gap in alloys x⩽0.25. Our results indicate an...
Ubiquitous post-consumer plastic waste is often physically mixed combining recalcitrant petroleum-based plastics with bioplastics, forming (petro-bio)plastic streams. Finding appropriate end-of-life (EoL) strategies for highly pertinent in achieving environmental protection, sustainability value chain industries including recyclers and government policy makers worldwide. The presence of bioplastic polyethylene terephthalate (PET) or other streams poses a substantial drawback to mechanical...
In this work, we investigate structural and optical properties of metalorganic chemical vapor deposition grown wurtzite InxGa1−xN/GaN epitaxial layers with thicknesses that are close to the critical layer thickness (CLT) for strain relaxation. CLT structures was calculated as a function InN content, x, using energy balance model proposed by People Bean [Appl. Phys. Lett. 47, 322 (1985)]. Experimentally determined in good agreement these calculations. The occurrence discontinuous relaxation...
The presence of two, or more, x-ray diffraction (XRD) peaks from an InGaN epilayer is sometimes regarded as indicator phase segregation. Nevertheless, detailed characterization InGaN/GaN bilayer by a combination XRD and Rutherford backscattering spectrometry (RBS) shows that splitting the peak may be completely unrelated to decomposition. Wurtzite layers were grown in commercial reactor. An reciprocal space map performed on (105) plane one component partially resolved double practically...
The circular economy is emerging with new sustainable solutions to the ever-growing plastic waste challenge, garnering increasing attention. In this study, possibility modify expensive Hestrin–Schramm medium (HS) for bacterial nanocellulose (BNC) production and replace significant amounts of glucose terephthalic acid (TPA) derived after reactive extrusion processing mixed yielding post consumer TPA (pcTPA), was evaluated from laboratory scale fermentation at pilot scale. Fourier-transform...
Even in good quality undoped GaN samples, as assessed by the intense excitonic emission, yellow band is present. This has been attributed either to a shallow donor deep double pair recombination [1], acceptor [2] or and state [3]. However, its origin not yet clear. We present data on time resolved spectroscopy compared with steady results. These results indicate that there no difference shape between spectra at all temperatures. some samples an increase intensity of band. It concluded...
Abstract This study explores the biodegradation potential of microbial isolates focusing on their ability to utilize biopolymers as sole carbon source. Previously described have been investigated through agar-based screen for degrade plastic-related substrates in powder form, and four strains selected further assessment. Polyhydroxybutyrate (PHB) films degradation was examined liquid culture, soil burial, respirometry assays. Structural chemical alterations PHB were analysed using scanning...
This contribution is focused on Raman analysis of the InxGa1−xN alloy. It presents direct evidence that both strain and composition effects must be taken into account to interpret experimental results. studies have been commonly discussed in view inhomogeneity only, neglecting possible existence depth variations, recently shown occur for layers grown above critical layer thickness. The this variation A1(LO) phonon frequency could only investigated by combining structural measurements. In...
We report a detailed compositional analysis of InxGa1−xN/GaN multiple quantum wells (MQWs) grown by metalorganic chemical vapor deposition. Depth profiles the InN fraction, x, in MQWs were determined from grazing incidence Rutherford backscattering spectroscopy (RBS) analysis. Simulation RBS spectra provides precise estimations individual well compositions, thickness, and extent In/Ga intermixing. It is ascertained that intermixing, In segregation to GaN cap layer, strongly increase with...
Substitutional ${\mathrm{Ni}}^{\mathrm{\ensuremath{-}}}$ in synthetic diamonds has been investigated by electron-paramagnetic resonance (EPR) and photo-EPR. The photo-EPR investigation shows that the EPR signal can be diminished optical illumination, threshold energy of 2.47\ifmmode\pm\else\textpm\fi{}0.02 eV suggests acceptor level is located at 3.03 above valence band. dependence cross section for electron ionization ${\mathrm{\ensuremath{\sigma}}}_{\mathit{n}}$ was determined from an...
A depth resolved study of optical and structural properties in wurtzite InGaN/GaN bilayers grown by MOCVD on sapphire substrates is reported. Depth cathodoluminescence (CL), Rutherford backscattering spectrometry (RBS) high resolution X-ray diffraction (HRXRD) were used to gain an insight into the composition strain profiles. It found that both quantities can vary considerably over depth. Two representative samples are discussed. The first shows a CL peak shift blue when electron beam energy...