Special Issue "Advances in Structural and Compositional Characterization for the Development of Wide Bandgap Semiconductors"

A special issue of Crystals (ISSN 2073-4352). This special issue belongs to the section "Crystalline Materials".

Deadline for manuscript submissions: 31 March 2019

Special Issue Editors

Guest Editor
Prof. Dr. Katharina Lorenz

Tecnologias Nucleares e Protecção Radiológica; Departamento de Engenharia e Ciências Nucleares
Website | E-Mail
Interests: wide bandgap semiconductors; nanotechnology; ion beam analysis; ion beam modification
Guest Editor
Dr. Andrés Redondo-Cubero

Department of Applied Physics, Universidad Autónoma de Madrid, Madrid E-28049, Spain
Website | E-Mail
Interests: wide bandgap semiconductors; nanotechnology; ion beam analysis; ion beam modification; nanopatterning; crystalline structures

Special Issue Information

Dear Colleagues,

Wide bandgap semiconductors (WBGS) are the key to a new generation of electronic and optoelectronic devices with functionalities going beyond those of silicon devices. The overwhelming success of III-nitride based light emitting diodes (LEDs) and laser diodes used in solid state lighting applications and data storage is a prominent example. High power and high temperature electronic devices, today mainly built from SiC and GaN, find use in various fields from renewable energy generation, over electric vehicles, to transportation and space applications, just to name a few. Further fields of applications where WBGS are expected to play a prominent role include RF devices for space communications, sensors, quantum technologies, among others. In this scenario, emerging wide bandgap semiconductors such as ZnMg(Cd)O, Ga2O3 or diamond are about to reveal their full potential.

The performance of any device based on these novel materials will depend critically on the structural and compositional properties of the constituent semiconductor material. Advanced characterisation techniques are therefore needed to reveal the physical mechanisms leading to certain desired or unintended features such as certain microstructures, defects, strain, doping, etc. The objective of this Special Issue is therefore to highlight the importance of structural and compositional characterisation for the development of novel WBGS structures and devices and to give a series of representative examples of how advanced structural and compositional characterisation can help to control the desired properties and functions of materials and devices.

  • All wide bandgap semiconductors (WBGS) including nitrides, carbides, oxides, diamond and other emerging materials with different shapes and scales from bulk crystals to nanostructures;
  • Application of advanced structural and compositional characterisation to WBGS including X-Ray-based techniques, electron microscopy-based techniques, ion beam analysis techniques, nuclear probe techniques, imaging techniques, spectroscopies, surface sensitive techniques;
  • Micro and nanomechanical properties of WBGS;
  • In-situ characterisation;
  • Defects, dislocations, deformation, twins, and stress induced phenomena in WBGS;
  • Advances in materials modeling of WBGS;
  • Optimisation of growth procedures based on structural/compositional properties;
  • Doping;
  • Structural modification of WBGS including processing by etching, surface treatments, patterning, annealing, irradiation, implantation;
  • Fabrication and functionalisation;
  • WBGS device optimisation based on structural and compositional characterisation for applications in optoelectronics, high-power electronics, photonics, sensors, energy and other emerging technologies.

Prof. Dr. Katharina Lorenz
Dr. Andrés Redondo-Cubero
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Crystals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1200 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Wide bandgap semiconductors
  • Heterostructures
  • Nanostructures
  • WBGS growth
  • Doping
  • Structural characterization
  • Compositional characterization
  • Defects, strain, microstructure
  • Materials processing and device fabrication
  • Relationship structural/compositional properties-device performance

Published Papers (2 papers)

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Research

Open AccessArticle Influence of Pressure on the Mechanical and Electronic Properties of Wurtzite and Zinc-Blende GaN Crystals
Crystals 2018, 8(11), 428; https://doi.org/10.3390/cryst8110428
Received: 19 October 2018 / Revised: 7 November 2018 / Accepted: 8 November 2018 / Published: 14 November 2018
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Abstract
The mechanical and electronic properties of two GaN crystals, wurtzite and zinc-blende GaN, under various hydrostatic pressures were investigated using first principles calculations. The results show that the lattice constants of the two GaN crystals calculated in this study are close to previous
[...] Read more.
The mechanical and electronic properties of two GaN crystals, wurtzite and zinc-blende GaN, under various hydrostatic pressures were investigated using first principles calculations. The results show that the lattice constants of the two GaN crystals calculated in this study are close to previous experimental results, and the two GaN crystals are stable under hydrostatic pressures up to 40 GPa. The pressure presents extremely similar trend effect on the volumes of unit cells and average Ga-N bond lengths of the two GaN crystals. The bulk modulus increases while the shear modulus decreases with the increase in pressure, resulting in the significant increase of the ratios of bulk moduli to shear moduli for the two GaN polycrystals. Different with the monotonic changes of bulk and shear moduli, the elastic moduli of the two GaN polycrystals may increase at first and then decrease with increasing pressure. The two GaN crystals are brittle materials at zero pressure, while they may exhibit ductile behaviour under high pressures. Moreover, the increase in pressure raises the elastic anisotropy of GaN crystals, and the anisotropy factors of the two GaN single crystals are quite different. Different with the obvious directional dependences of elastic modulus, shear modulus and Poisson’s ratio of the two GaN single crystals, there is no anisotropy for bulk modulus, especially for that of zinc-blende GaN. Furthermore, the band gaps of GaN crystals increase with increasing pressure, and zinc-blende GaN has a larger pressure coefficient. To further understand the pressure effect on the band gap, the band structure and density of states (DOSs) of GaN crystals were also analysed in this study. Full article
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Open AccessArticle Study of Nanoscratching Process of GaAs Using Molecular Dynamics
Crystals 2018, 8(8), 321; https://doi.org/10.3390/cryst8080321
Received: 14 July 2018 / Revised: 3 August 2018 / Accepted: 9 August 2018 / Published: 11 August 2018
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Abstract
In this paper, molecular dynamics method was employed to investigate the nanoscratching process of gallium arsenide (GaAs) in order to gain insights into the material deformation and removal mechanisms in chemical mechanical polishing of GaAs. By analyzing the distribution of hydrostatic pressure and
[...] Read more.
In this paper, molecular dynamics method was employed to investigate the nanoscratching process of gallium arsenide (GaAs) in order to gain insights into the material deformation and removal mechanisms in chemical mechanical polishing of GaAs. By analyzing the distribution of hydrostatic pressure and coordination number of GaAs atoms, it was found that phase transformation and amorphization were the dominant deformation mechanisms of GaAs in the scratching process. Furthermore, anisotropic effect in nanoscratching of GaAs was observed. The diverse deformation behaviors of GaAs with different crystal orientations were due to differences in the atomic structure of GaAs. The scratching resistance of GaAs(001) surface was the biggest, while the friction coefficient of GaAs(111) surface was the smallest. These findings shed light on the mechanical wear mechanism in chemical mechanical polishing of GaAs. Full article
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