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Your search keyword '"Barkay, Z."' showing total 183 results
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183 results on '"Barkay, Z."'

1. Crystallographic orientation errors in mechanical exfoliation

Author

Kolumbus, Y., Zalic, A., Fardian-Melamed, N., Barkay, Z., Rotem, D., Porath, D., and Steinberg, H.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Materials Science
Abstract

We evaluate the effect of mechanical exfoliation of van der Waals materials on crystallographic orientations of the resulting flakes. Flakes originating from a single crystal of graphite, whose orientation is confirmed using STM, are studied using facet orientations and electron back-scatter diffraction (EBSD). While facets exhibit a wide distribution of angles after a single round of exfoliation ($ \sigma \approx 5^o $), EBSD shows that the true crystallographic orientations are more narrowly distributed ($ \sigma \approx 1.5^o $), and facets have an approximately error from the true orientation. Furthermore, we find that the majority of graphite fractures are along armchair lines, and that the cleavage process results in an increase of the zigzag lines portion. Our results place values on the rotation caused by a single round of the exfoliation process, and suggest that when a 1-2 degree precision is necessary, the orientation of a flake can be gauged by the orientation of the macroscopic single crystal from which it was exfoliated.

Published
2020
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12. Nanoscale potential distribution across multiquantum well structures: Kelvin probe force microscopy and secondary electron imaging

Author

Schwarzman, A., Barnham, K., Strassburg, E., Barkay, Z., Grunbaum, E., Mazzer, M., Lepkifker, E., Glatzel, Th., Boag, A., and Rosenwaks, Y.

Subjects
Quantum wells -- Structure, Electron microscopy -- Usage, Gallium arsenide semiconductors -- Design and construction, Physics
Abstract

In0.17GaAs/GaAsP0.06 multiquantum well structures, together with secondary electron microscopy are characterized using ultrahigh vacuum cross-sectional Kelvin probe force microscopy. Individual 8 nm quantum wells are well resolved in both methods, and are found to be in good agreement with numerical simulations of the work function profile.

Published
2005

16. Low current electroplastic effect in ferromagnetic materials

Author

Parkansky, N., Molotskii, M., Alterkop, B., Goldsmith, S., Boxman, R.L., Rosenberg, Y., and Barkay, Z.

Subjects
Ferromagnetic materials -- Research, Physics -- Research, Physics
Abstract

Research describing indentation testing on nickel and copper samples with low current flow is presented. The low current electroplastic effect is examined with respect to the magnetic structure of the metals under test.

Published
2001

18. Effect of substrate defects on the properties of high Tc superconducting thin films

Author

Barkay, Z., Racah, D., Grunbaum, E., and Deutscher, G.

Subjects
Superconductors -- Analysis, Physics
Abstract

The results of the study on the influence of substrate defects on the morphological and transport properties of Y1Ba2Cu3O(sub 7-x) high T(sub c) superconducting films, reveal that substrate defects are characterized by dispersive and nondispersive cathodoluminescence in the scanning electron microscope. The secondary electrons were utilized in the study of the morphology of the films and the results were compared with the substrate information.

Published
1993

24. Secondary electron doping contrast: Theory based on scanning electron microscope and Kelvin probe force microscopy measurements.

Author

Volotsenko, I., Molotskii, M., Barkay, Z., Marczewski, J., Grabiec, P., Jaroszewicz, B., Meshulam, G., Grunbaum, E., and Rosenwaks, Y.

Subjects
SEMICONDUCTOR doping, SCANNING electron microscopy, ELECTRON emission, SEMICONDUCTOR junctions, SILICON
Abstract

The secondary electron emission flux in a scanning electron microscope is a powerful tool for delineation of electrically active dopant concentration, built-in potentials, and surface electric fields in semiconductor junctions. In all the secondary electron images of p-n junctions, the p-doped regions appear brighter than n-doped regions. We present a theory for the doping contrast in p-n junctions that is based on the secondary electron emission yield and surface band bending extracted from Kelvin probe force microscopy measurements. We show that the contrast is governed by the secondary electron escape depth, and their escape probability which is related to the secondary electron energy distribution and the effective electron affinity. It is found that the escape depth is the main factor determining the dopant contrast, and the escape probability has a smaller effect. In addition, our theory explains the logarithmic dependence of the measured contrast on the acceptor concentration in silicon reported by many groups. [ABSTRACT FROM AUTHOR]

Published
2010
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37. Cathodoluminescence Image Processing of High TC Superconductors

Author

Barkay, Z., Deutscher, G., and Grunbaum, E.

Subjects
thin film, Cathodoluminescence, image-processing, carrier life-time, high-TC superconductors, YBaCuO, Biology, scanning electron microscopy
Abstract

Cathodoluminescence (CL) in the Scanning Electron Microscope (SEM) was performed for both ceramic pellets and thin films of YBaCuO high TC superconductors. Image processing provided additional quantitative information. For single phase films, we demonstrated the possibility to create thickness maps in real time from the CL pictures. The gradual thickness variation within the sample was revealed by the histogram of the thickness image. The continuity of the film was observed at a few threshold thicknesses values, defined by the fraction of the occupied area. At the conduction threshold value, the location and width of the conducting paths could be estimated. The analysis was of a lateral resolution better than 1 μm and of a submicron thickness resolution. Insulating impurity grains embedded in the YBaCuO ceramic pellet, which could not be recognized by secondary electrons, were revealed by the CL mode in the SEM. Their long luminescence lifetime was recorded at different time scales and provided an estimation of the lifetime and density of generated carriers. This analysis can be applied to any other high TC superconductors.

Published
1992

45. The electric field and dopant distribution in p-i-n structures observed by ionisation potential (dopant contrast) microscopy in the HRSEM.

Author

Cullis, A. G., Hutchison, J. L., Grunbaum, E., Barkay, Z., Shapira, Y., Barnham, K., Bushnell, D. B., Ekins-Daukes, N. J., Mazzer, M., and Wilshaw, P. R.

Abstract

The method of ionisation potential (dopant contrast) microscopy in the HRSEM is applied to the study of the electric field distribution in p-i-n structures used as quantum well solar cells. Our results show a secondary electron signal which varies between the different layers, being greatest in the p-type and smallest in the n-type regions respectively. The stacks of 8 nm wide quantum wells and their corresponding barriers are clearly distinguished in the intrinsic region of the devices. In-situ observation of reverse biased structures has been performed to determine the effect of bias on the potential distribution within the devices. [ABSTRACT FROM AUTHOR]

Published
2005
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