Article
Crystallography
Piotr Mazur, Agata Sabik, Rafal Lewandkow, Artur Trembulowicz, Milosz Grodzicki
Summary: In this work, a niobium nitride film was obtained using n-GaN(1000) surface as the source of nitrogen atoms through a surface-mediated nitridation technique. The deposition of niobium film on GaN followed by sample annealing resulted in the formation of a niobium nitride compound containing Nb from the thin film and N atoms from the substrate. The structural, chemical, and surface properties of both the GaN substrate and NbNx films were studied using in-situ techniques.
Article
Materials Science, Coatings & Films
J. G. Tobin
Summary: The study focuses on the electronic structure of the close-packed metal overlayer system on the Cu(001) surface, covering the evolution from two-dimensional behavior at low coverages to three-dimensional behavior, and the convergence to three-dimensional dispersion observed in Ag(111). The research aims to understand the specific placement of the first monolayer Ag atoms on the Cu(001) substrate, but limitations in information extraction using photon-induced electron diffraction will be demonstrated with FEFF.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2021)
Article
Chemistry, Multidisciplinary
Chenguang Zhang, Wenliang Wang, Xiaodong Hao, Yong Peng, Yulin Zheng, Jia Liu, Yiyuan Kang, Fujian Zhao, Zhengtang Luo, Junjie Guo, Bingshe Xu, Longquan Shao, Guoqiang Li
Summary: This study utilized GaN/AlGaN materials with controlled polarity to induce endogenous electrical stimulation for bone regeneration, finding that Ga-polarity GaN/AlGaN nanofilms showed superior bone repair in vivo and promoted osteogenic differentiation of bone mesenchymal stem cells in vitro. Additionally, the study revealed that bone morphogenetic protein-6 (BMP6) may be an electrically sensitive osteogenic protein.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Yixin Xiao, Srinivas Vanka, Tuan Anh Pham, Wan Jae Dong, Yi Sun, Xianhe Liu, Ishtiaque Ahmed Navid, Joel B. Varley, Hamed Hajibabaei, Thomas W. Hamann, Tadashi Ogitsu, Zetian Mi
Summary: Tuning the surface structure of gallium nitride (GaN) photoelectrodes is an effective approach to address challenges in artificial photosynthesis. Nonpolar surfaces of GaN exhibit significant photoelectrochemical activity, while polar c-plane surfaces show little to no activity. Density functional theory calculations provide insight into the atomic origin of this difference.
Article
Multidisciplinary Sciences
Abdelmalek Taoutioui, Karoly Tokesi
Summary: This paper presents numerical investigations of strong-field attosecond photoelectron holography in hydrogen atom target induced by a strong infrared laser pulse. The effects of the number of optical cycles and the intensity and wavelength of the laser pulse on the holographic interference structures in the two-dimensional photoelectron momentum distribution (PMD) are analyzed. The results show that the number of optical cycles affects the formation of interference patterns, and the intensity and wavelength of the laser pulse affect the density of interference fringes in the holographic patterns.
SCIENTIFIC REPORTS
(2022)
Article
Chemistry, Physical
Hiroshi Daimon, Ikko Tanaka
Summary: The dependence of forward scattering peak intensity on Z and the value of alpha were discussed in this article. It was found that Z-dependence plays a significant role in elemental analysis.
CHEMICAL PHYSICS LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Takato Fukui, Yoshinobu Matsuda, Makoto Matsukura, Takahiro Kojima, Mitsuru Funato, Yoichi Kawakami
Summary: GaN layers are grown on Al-pretreated ScAlMgO4 substrates using MOVPE without LT buffer layers. The Al pretreatment results in the nucleation of AlN on ScAlMgO4. The GaN MOVPE inverts the polarity from N-polar to metal polar, leading to better crystalline quality compared with conventional LT-buffer technology.
CRYSTAL GROWTH & DESIGN
(2023)
Article
Materials Science, Multidisciplinary
Sida Wei, Jing Wang, Xiaodan Wang, Xiaodong Gao, Jiafan Chen, Hongmin Mao, Xionghui Zeng, Ke Xu
Summary: This study investigates the influence of free-standing GaN substrates with different polarities on the surface morphologies and physical properties of epitaxial Mg-doped GaN films grown by MOCVD. The films grown on polar, semipolar, and nonpolar FS-GaN substrates show varying surface morphologies due to different surface states and growth modes. Despite the differences, all films exhibit high crystalline quality and are mostly stress-free.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Krishna Yaddanapudi, Sabyasachi Saha, Kuttanellore Muraleedharan, Dipankar Banerjee
Summary: This study demonstrates the influence of metalorganic chemical vapor deposition process parameters on the evolution of gallium nitride (GaN) and focuses on nitrogen-polar GaN (N-polar GaN). The research shows that N-polar GaN epilayers formed at low epilayer growth temperatures have high surface quality and good crystalline quality.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Richard J. Wilbraham, Elizabeth A. Howett, Colin Boxall, David I. Hambley, Jessica K. Higgins
Summary: This paper presents a detailed study on the chemical and materials characterization of novel Simulated Spent Nuclear Fuels (SIMFuel) that replicate the state of Spent Nuclear Fuel (SNF) discharged from a UK Advanced Gas-cooled Reactor (AGR). The study evaluates the use of XPS, micro-Raman spectroscopy, and XRD in characterizing SIMFuels, and reveals the effects of lanthanide dopants on the UO2 bulk matrix. The findings suggest the presence of U(V) in the UO2 matrix as a means of charge compensation for the incorporation of Ln(III) states, and provide insights into the O/U ratios in SIMFuels.
JOURNAL OF NUCLEAR MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Sho Ito, Fraser J. White, Eiji Okunishi, Yoshitaka Aoyama, Akihito Yamano, Hiroyasu Sato, Joseph D. Ferrara, Michal Jasnowski, Mathias Meyer
Summary: 3D electron diffraction/Micro electron diffraction techniques have expanded the possibilities of crystallography for determining three-dimensional molecular structures from sub-micrometer microcrystals. However, current measurements using advanced electron microscopes require expertise in both electron microscopy and crystallography, making it challenging for researchers. The newly developed electron diffractometer offers an easier path for many researchers to determine crystal structures smaller than 1 micrometer in size.
Article
Chemistry, Physical
Yangfeng Li, Xiaotao Hu, Yimeng Song, Zhaole Su, Wenqi Wang, Haiqiang Jia, Wenxin Wang, Yang Jiang, Hong Chen
Summary: This study investigates the influence of aluminum nitride (AlN) thickness on the N-polar gallium nitride (GaN) grown by metal organic chemical vapor deposition (MOCVD). Controllable polarity inversion through changing the thickness of AlN provides a promising method for polarity engineering of nitride-based devices. The thickness of AlN plays a critical role in determining the surface morphology, crystalline quality, and polarity of the grown N-polar GaN thin film.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Physics, Applied
Kelsey J. Mirrielees, J. Houston Dycus, Jonathon N. Baker, Pramod Reddy, Ramon Collazo, Zlatko Sitar, James M. LeBeau, Douglas L. Irving
Summary: Properties of AlN/GaN surfaces play a crucial role in device tunability and performance, affecting Fermi level pinning and surface passivation. Various models and methods are used to address challenges related to surface oxidation and reconstruction, with direct observation of reconstructions providing valuable insights. The presence of cation-deficient structures in the observed reconstructions explains surface states consistent with experimental observations, improving the understanding of oxidized AlGaN surfaces.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Physical
Nadezhda V. Vladimirova, Alexander S. Frolov, Jaime Sanchez-Barriga, Oliver J. Clark, Fumihiko Matsui, Dmitry Yu Usachov, Matthias Muntwiler, Carolien Callaert, Joke Hadermann, Vera S. Neudachina, Marina E. Tamm, Lada Yashina
Summary: Occupancy of different structural positions in a crystal lattice plays a key role in material properties. X-ray Photoelectron Diffraction (XPD) is a surface science structural method that can be used for occupancy analysis. By studying Sb2(Te1-xSex)3 mixed crystals, we found that XPD data showed excellent agreement with the reference method. We also discovered significant differences in anion occupancy between the surface and bulk.
SURFACES AND INTERFACES
(2023)
Article
Physics, Multidisciplinary
Amit Kumar Mauraya, Debashrita Mahana, Prashant Tyagi, Ch Ramesh, Ajay Kumar Shukla, Sudhir Husale, Sunil Singh Kushvaha, Muthusamy Senthil Kumar
Summary: The influence of using different types of GaN targets on the surface morphology and structural quality of GaN epilayers was studied, with confirmation through X-ray rocking curve measurements and X-ray photoelectron spectroscopy. Further investigation was conducted on the effect of threading dislocation density on the ultraviolet photoresponse properties of GaN layers using metal-semiconductor-metal structures.
Article
Chemistry, Physical
P. Hauschwitz, R. Jagdheesh, D. Rostohar, J. Brajer, J. Kopecek, P. Jiricek, J. Houdkova, T. Mocek
APPLIED SURFACE SCIENCE
(2020)
Article
Materials Science, Multidisciplinary
Eva Horynova, Oleksandr Romanyuk, Lukas Horak, Zdenek Remes, Brianna Conrad, Amalraj Peter Amalathas, Lucie Landova, Jana Houdkova, Petr Jiricek, Tomas Finsterle, Jakub Holovsky
Article
Chemistry, Physical
I Bieloshapka, P. Jiricek, Y. Yakovlev, K. Hruska, E. Tomsik, J. Houdkova, A. Malolepszy, M. Mazurkiewicz, Y. Lobko, B. Lesiak
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2020)
Article
Chemistry, Physical
O. Romanyuk, I. Gordeev, A. Paszuk, O. Supplie, J. P. Stoeckmann, J. Houdkova, E. Ukraintsev, I. Bartos, P. Jiricek, T. Hannappel
APPLIED SURFACE SCIENCE
(2020)
Article
Chemistry, Physical
Oleksandr Romanyuk, Oliver Supplie, Agnieszka Paszuk, Jan Philipp Stoeckmann, Regan George Wilks, Jakob Bombsch, Claudia Hartmann, Raul Garcia-Diez, Shigenori Ueda, Igor Bartos, Ivan Gordeev, Jana Houdkova, Peter Kleinschmidt, Marcus Baer, Petr Jiricek, Thomas Hannappel
SURFACE AND INTERFACE ANALYSIS
(2020)
Article
Materials Science, Coatings & Films
R. Hippler, M. Cada, P. Ksirova, J. Olejnicek, P. Jiricek, J. Houdkova, H. Wulff, A. Kruth, C. A. Helm, Z. Hubicka
Summary: Cobalt oxide films were deposited using two different magnetron sputtering techniques under different oxygen atmospheres, demonstrating that films produced by HiPIMS process have better performance and lower resistivity. The deposition conditions of magnetron sputtering have a significant impact on the crystal structure and electrical properties of the deposited films.
SURFACE & COATINGS TECHNOLOGY
(2021)
Article
Chemistry, Physical
J. Zemek, J. Houdkova, P. Jiricek, M. Jelinek, K. Jurek, T. Kocourek, M. Ledinsky
Summary: The study used ARXPS and MEM techniques to analyze the surface composition and chemical bonds of calcium-doped DLC layers, revealing significant variations in compounds and chemical bonds between the surface and shallow sub-surface regions.
APPLIED SURFACE SCIENCE
(2021)
Article
Chemistry, Physical
Stepan Stehlik, Michel Mermoux, Bernhard Schummer, Ondrej Vanek, Katerina Kolarova, Pavla Stenclova, Ales Vlk, Martin Ledinsky, Rene Pfeifer, Oleksandr Romanyuk, Ivan Gordeev, Francine Roussel-Dherbey, Zuzana Nemeckova, Jiri Henych, Petr Bezdicka, Alexander Kromka, Bohuslav Rezek
Summary: The study investigated the effects of size on the surface chemistry, microscopic structure, and Raman scattering of nanodiamonds, revealing size-dependent and synthesis-dependent differences in their properties. By analyzing particle size distribution and comparing detonation and high-pressure high-temperature nanodiamonds, the study identified effects of diamond core size, defects, chemical stability, and phonon confinement models. Additionally, low-frequency Raman scattering was observed, suggesting confined acoustic vibrational modes in the nanodiamonds.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Optics
Jiri Schmidt, Karel Kolacek, Alexandr Frolov, Jaroslav Straus, Petr Hoffer, Vitaliy Stelmashuk, Andrii Tuholukov, Petr Jiricek, Jana Houdkova
Summary: This paper investigates the transmittance and oxidation issues of thin-film Al filters, revealing that the amorphous Al2O3 layers have a significant impact on the total transmittance of the filters.
Article
Chemistry, Multidisciplinary
Irena Bydzovska, Ekaterina Shagieva, Ivan Gordeev, Oleksandr Romanyuk, Zuzana Nemeckova, Jiri Henych, Lukas Ondic, Alexander Kromka, Stepan Stehlik
Summary: Laser irradiation of de-aggregated hydrogenated DNDs dispersed in ethanol can effectively lead to the formation of onion-like carbon (OLC). Increased irradiation time results in the gradual loss of nanoparticle characteristics and the recovery of typical DND Raman spectrum after annealing at 450 degrees C for 300 min. This study demonstrates the inhomogeneous sp(3) to sp(2) carbon transformation during laser irradiation and the insensitivity of DND Raman spectra to surface chemistry, size, and transient structural changes.
Article
Chemistry, Physical
O. Romanyuk, A. Paszuk, I Bartos, R. G. Wilks, M. Nandy, J. Bombsch, C. Hartmann, R. Felix, S. Ueda, I Gordeev, J. Houdkova, P. Kleinschmidt, P. Machek, M. Baer, P. Jiricek, T. Hannappel
Summary: The atomic structure and electronic properties of GaP/Si(0 0 1) heterointerfaces were investigated using hard X-ray photoelectron spectroscopy (HAXPES). Analysis of core level photoelectron intensities revealed shifts in core level peaks and proposed an Inter-Diffused Layer (IDL) model for the interfacial structure. A new Parametrized Polynomial Function (PPF) approach was used to derive non-monotonic band bending profiles in the heterostructures and determine valence band discontinuities at GaP/Si(0 0 1) interfaces.
APPLIED SURFACE SCIENCE
(2021)
Article
Chemistry, Physical
Ghulam Abbas, Farjana J. Sonia, Zahid Ali Zafar, Karel Knizek, Jana Houdkova, Petr Jiricek, Milan Bousa, Jan Plsek, Martin Kalbac, Jiri Cervenka, Otakar Frank
Summary: Graphite intercalation compounds (GICs) are known for their diverse physicochemical properties and applications, with properties depending on synthesis technique, structure, morphology, intercalant species, and concentration. This study investigated ClO4- anion intercalation in two types of graphite, revealing differences in electrochemical behavior correlated with structural properties. Such findings offer new perspectives for GIC formation and electrochemical energy storage applications.
Article
Optics
Tomas Zikmund, Jiri Bulir, Michal Novotny, Petr Jiriek, Jana Houdkova, Jan Lancok
Summary: The presence of a metal surface near a fluorophore can significantly alter its luminescent properties, with effects depending on the nature of the transition. The optimal distance between the metal and fluorophore has been identified, and different excitation methods also impact the fluorescence results.
JOURNAL OF LUMINESCENCE
(2022)
Article
Chemistry, Physical
O. Romanyuk, A. Paszuk, I Gordeev, R. G. Wilks, S. Ueda, C. Hartmann, R. Felix, M. Baer, C. Schlueter, A. Gloskovskii, I Bartos, M. Nandy, J. Houdkova, P. Jiricek, W. Jaegermann, J. P. Hofmann, T. Hannappel
Summary: This study investigates the epitaxial growth of GaP films on As-terminated Si substrates and reveals the localization of As atoms in the GaP lattice and at the GaP/Si interface. Chemical shifts in As core levels were observed, and similar valence band offset values were obtained regardless of the doping type, substrate miscut, or As-terminated surface of the Si substrate. The band alignment diagram of the GaP(As)/Si(100) heterostructure was also deduced.
APPLIED SURFACE SCIENCE
(2022)
Article
Physics, Applied
A. Hrubantova, R. Hippler, H. Wulff, M. Cada, O. Gedeon, P. Jiricek, J. Houdkova, J. Olejnicek, N. Nepomniashchaia, C. A. Helm, Z. Hubicka
Summary: Copper tungsten oxide films were deposited using reactive high power impulse magnetron sputtering in an argon/oxygen gas mixture. The films' composition, crystal structure, and photoelectrochemical activity were characterized using various techniques.
JOURNAL OF APPLIED PHYSICS
(2022)
