Undoped ZnO single crystals were implanted with aluminum ions up to a dose of 10Al/cm. Vacancy defects in the implanted layers were detected using positron lifetime and Doppler broadening measurements with slow positron beams. It shows that vacancy clusters, which are close to the size of V8, are generated by implantation. Postimplantation annealing shows that the Doppler broadening S parameter...

Dynamic structural changes during the first electrochemical charge and discharge cycle in the Li-excess layered oxide compound, Li[Li1/5Ni1/5Mn3/5]O2, are studied with synchrotron X-ray diffraction (SXRD), aberration corrected scanning transmission electron microscopy (a-S/TEM), and electron energy loss spectroscopy (EELS). At different states of charge, we carefully examined the crystal struct...

A detailed first-principles study of the interactions of hydrogen with different point defects in Ni is presented. In particular we discuss the trapping of multiple hydrogen atoms in monovacancies, divacancies and at the self-interstitial (dumbbell). We show that, contrary to the previous theoretical works, the dumbbell cannot trap H atoms. In the case of a single vacancy, the segregation energ...

We have investigated the effects of helium ion irradiation energy and sample temperature on the performance of grain boundaries as helium sinks in ultrafine grained and nanocrystalline tungsten. Irradiations were performed at displacement and non-displacement energies and at temperatures above and below that required for vacancy migration. Microstructural investigations were performed using Tra...

The basal plane of graphene has been known to be less reactive than the edges, but some studies observed vacancies in the basal plane after reaction with oxygen gas. Observation of these vacancies has typically been limited to nanometer-scale resolution using microscopic techniques. This work demonstrates the introduction and observation of subnanometer vacancies in the basal plane of graphene ...

B. K. Ofori-Okai,1 S. Pezzagna,2 K. Chang,3 M. Loretz,3 R. Schirhagl,3 Y. Tao,1,3 B. A. Moores,3 K. Groot-Berning,2 J. Meijer,2 and C. L. Degen3,* 1Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA 2RUBION, Ruhr-Universitaet Bochum, Universitaetsstrasse 150, 44780 Bochum, Germany 3Department of Physics, ETH Zurich, Schaf...

Magnetism of graphene can be created by atomic defects, either hydrogen adsorption or single-carbon vacancy formation, owing to the unpaired $\ensuremath{\pi}$ electrons around defects. Here we explore, based on rigorous first principles calculations, possibility voltage manipulation two such types magnetism in via a scanning tunneling microscope tip. We find remarkably different behavior. For ...

We have observed charge trapping during constant voltage stress in Hf-based highdielectrics at deep traps as well as at the shallow traps. VFB and leakage current dependence on these deep traps further suggest that trapping at deep levels inhibits fast VT recovery. The earlier findings where charge trapping seemed to be very transient due to the presence of a large number of shallow traps and t...

The defect structure of CdTe substrates has often been investigated with luminescence techniques. In particular, a luminescence band normally referred as the 1.40 eV band, has been associated with recombination processes involving defects but its nature seems to be complex. Myers et al.’ in their photoluminescence study of CdTe wafers concluded that a significant part of the 1.40 eV band is dir...

It is demonstrated that the support effects play a crucial role in the gold nanocatalysis. Two types of support are considered—the “inert” support of hexagonal boron nitride (h-BN) with the N and B vacancy defects and the “active” support of rutile TiO2(110). It is demonstrated that Au and Au2 can be trapped effectively by the vacancy defects in h-BN. In that case, the strong adsorption on the ...