Structural and vibrational properties of wurtzite ZnO with oxygen-deficient defects: and potential-based calculations.

The structural and vibrational properties of the ZnO wurtzite phase with oxygen vacancies in different charged states are studied using first-principles and potential-based methods. The calculations based on density-functional theory are performed to determine the atomic configurations around defects. The DFT results are discussed and compared with those obtained using the static lattice method in the traditional shell model.

Schottky-Diode Design for Future High-Speed Telecommunications.

The impact of 5G communication is expected to be widespread and transformative. It promises to provide faster mobile broadband speeds, lower latency, improved network reliability and capacity, and more efficient use of wireless technologies. The Schottky diode, a BN/GaN layered composite contacting bulk aluminum, is theoretically plausible to harvest wireless energy above X-band.

Exciton Luminescence and Optical Properties of Nanocrystalline Cubic YO Films Prepared by Reactive Magnetron Sputtering.

This paper presents a comprehensive study of the energy structure, optical characteristics, and spectral-kinetic parameters of elementary excitations in a high-purity nanocrystalline cubic YO film synthesized by reactive magnetron sputtering. The optical transparency gaps for direct and indirect interband transitions were determined and discussed. The dispersion of the refractive index was established based on the analysis of interference effects.

Carbon Bond Breaking under Ar-Ion Irradiation in Dependence on sp Hybridization: Car-Parrinello, Ehrenfest, and Classical Dynamics Study.

The modeling of low-temperature plasma synthesis of low-dimensional carbon coatings remains a challenge, since the long-time spans must be simulated for structural relaxation. A proper theoretical method should be chosen to address possible charge-transfer processes. Considering the possibility of linear-chained carbon (LCC) synthesis simulation, a numerical study of the C-C bond breaking under slow argon-ion irradiation is performed for the model molecules of 2,2,3,3-tetramethylbutane (sp hybridization), 1,2,3-butatriene (sp), and 2-butyne (sp).

Defect structure and vibrational states in Eu-doped cubic gadolinium oxide.

We consider an effect of trivalent Eu impurities occupying two different crystallographic positions in cubic gadolinium oxide on its lattice structure and phonon spectrum. The numerical methods employed in the study take into account the shell model to describe interatomic interactions. Using cluster approach, the equilibrium lattice structures and phonon local symmetrized densities of states are calculated.

Kinetic selection of nonradiative excitation in photonic nanoparticles GdO:Er.

In the present work, we separate and classify four different pathways for UV-vis energy conversion with participation of Gd and Er ions located at dissimilar structural sites in the GdO lattice. The Gd centers represent host cations with a distorted environment due to the nearest defects of the anionic sublattice. Two non-equivalent types of both Gd donor and Er acceptor centers occupying C and S structural sites are selected in GdO:Er nanoparticles by the spectral-kinetic method.

Energy band gaps and excited states in Si QD/SiO /R O (R = Si, Al, Zr) suboxide superlattices.

X-ray and optical spectroscopies were applied in order to study the band structure and electronic excitations of the SiO /R O (R  =  Si, Al, Zr) suboxide superlattices. The complementary x-ray emission and absorption measurements allow for the band gap values for the SiO layers to be established, which are found to have almost no dependency on the cation type R. It is determined that, after annealing, the stoichiometric factor x remains near 1.

Interference effects in the UV(VUV)-excited luminescence spectroscopy of thin dielectric films.

The problem of exciting UV and VUV light interference affecting experimental photoluminescence excitation spectra is analysed for the case of thin transparent films containing arbitrarily distributed emission centres. A numerical technique and supplied software aimed at modelling the phenomenon and correcting the distorted spectra are proposed. Successful restoration results of the experimental synchrotron data for ion-implanted silica films show that the suggested method has high potential.