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Coalescence overgrowth of pattern-grown GaN nanocolumns (NC) on c-plane sapphire substrate with metal organic chemical vapour deposition is demonstrated. The subsequent coalescence overgrowth opens a possibility for dislocation reduction…

Mesoscale and Nanoscale Physics · Physics 2010-01-13 Hsiang-Chen Wang , Chun-Ming Yeh , Tsung-Yi Tang , C. C. Yang , T. Malinauskas , K. Jarasiunas

This work studies the effect of four different types of buffer layers on the structural and optical properties of InGaN layers grown on Si(111) substrates and their correlation with electrical characteristics. The vertical electrical…

Ga(In, Al)N alloys are used as an active layer or cladding layer in light emitting diodes and laser diodes. x-ray diffraction is extensively used to evaluate the crystalline quality, the chemical composition and the residual strain in…

Materials Science · Physics 2009-11-11 Zhou Sheng-Qiang , Wu Ming-Fang , Yao Shu-De

It is shown how the combination of atomic deposition and nonlinear diffusion may lead, below a critical temperature, to the growth of nonuniform layers on a substrate. The dynamics of such a system is of the Cahn-Hilliard type, supplemented…

Pattern Formation and Solitons · Physics 2013-07-22 Daniel Walgraef

The current method of growing large-area graphene on Cu surfaces (polycrystalline foils and thin films) and its transfer to arbitrary substrates is technologically attractive. However, the quality of graphene can be improved significantly…

Materials Science · Physics 2011-03-21 Kongara M. Reddy , Andrew D. Gledhill , Chun-Hu Chen , Julie M. Drexler , Nitin P. Padture

Barrier films preventing permeation of gases and moistures are important for many industries ranging from food to medical and from chemical to electronic. From this perspective, graphene has recently attracted particular interest because…

Materials Science · Physics 2014-11-19 Y. Su , V. G. Kravets , S. L. Wong , J. Waters , A. K. Geim , R. R. Nair

Superconductivity in granular films is controlled by the grain size and the inter-grain coupling. In a two-component granular system formed by a random mixture of a normal metal (N) and a superconductor (S), the superconducting nano-grains…

Mesoscale and Nanoscale Physics · Physics 2017-04-27 Pradnya Parab , Vivas Bagwe , Bhagyashree Chalke , H. Muthurajan , Pratap Raychaudhuri , Sangita Bose

The self-assembly of heteroepitaxial GaN nanowires using either molecular beam epitaxy (MBE) or metal-organic vapor phase epitaxy (MOVPE) mostly results in wafer-scale ensembles with ultrahigh ($>10$ $\mu$m$^{-2}$) or ultralow ($<1$…

Materials Science · Physics 2023-08-09 Thomas Auzelle , Miriam Oliva , Philipp John , Manfred Ramsteiner , Lutz Geelhaar , Oliver Brandt

Thin films of MgB2 superconductor were prepared by three different procedures on sapphire and silicon substrates. Boron thin films, ex-situ annealed in magnesium vapour, resulted in textured polycrystalline films with crystal dimensions…

Superconductivity · Physics 2009-11-07 A. Plecenik , L. Satrapinsky , P. Kus , S. Gazi , S. Benacka , I. Vavra , I. Kostic

Superconductivity has been found in RuN films obtained by reactive magnetron sputtering. This is a novel member of the metal nitride superconductors family. The critical temperature of the superconducting transition varies depending on the…

Nanoporous thin-films are an important class of materials, offering a way to observe fundamental surface and bulk processes with particles larger than individual atoms, but small enough to interact significantly with each other through…

Materials Science · Physics 2016-03-22 Jeffrey G. Ulbrandt , Yang Li , Randall L. Headrick

Top-down fabricated GaN nanowires, 250 nm in diameter and with various heights, have been used to experimentally determine the evolution of strain along the vertical direction of 1-dimensional objects. X-ray diffraction and…

The mechanical behavior of graphitic materials is greatly affected by the weak interlayer bonding with van der Waals forces for a range of thickness from nano to macroscale. Herein, we present a comprehensive study of the effect of layer…

We studied the magnetic properties of ferromagnetic-semiconductor composites based on nickel and porous-GaN, motivated by the effort to couple magnetic and semiconductor functionality. Nickel-infiltrated and nickel-coated (laminated…

AGN outflows can remove large quantities of gas from their host galaxy spheroids, potentially shutting off star formation. On the other hand, they can compress this gas, potentially enhancing or triggering star formation, at least for short…

Astrophysics of Galaxies · Physics 2017-04-27 Kastytis Zubovas , Martin A. Bourne

We report a new method for quantitative estimation of graphene layer thicknesses using high contrast imaging of graphene films on insulating substrates with a scanning electron microscope. By detecting the attenuation of secondary electrons…

Mesoscale and Nanoscale Physics · Physics 2012-03-28 Vidya Kochat , Atindra Nath Pal , Sneha E. S. , Arjun B. S. , Anshita Gairola , S. A. Shivashankar , Srinivasan Raghavan , Arindam Ghosh

Thin films containing casein appear to be a promising material for coatings used in the medical area to promote biomineralization. alfa- and beta-casein and poly-L-arginine multilayer films were formed by the layer-by layer technique and…

Soft Condensed Matter · Physics 2013-12-06 Lilianna Szyk Warszynska , Katarzyna Kilan , Robert P. Socha

We report on growth of tin (Sn) metal whiskers that is significantly accelerated under gamma-ray irradiation. The studied Sn thin film, evaporated on glass substrate, was subjected to a total of ~60 hours of irradiation over the course of…

MgB2 thin films were cold-grown on sapphire substrates by pulsed laser deposition (PLD), followed by post-annealing in mixed, reducing gas, Mg-rich, Zr gettered, environments. The films had Tcs in the range 29 K to 34 K, Jcs (20K, H=0) in…

We reported on the observation of extremely high-density ($>10^{14}$cm$^{-2}$) 2D electron gas in N-polar AlGaN/GaN heterostructures grown on sapphire substrates. Due to introducing the GaN/AlN superlattice (SL) back barrier between the GaN…

Mesoscale and Nanoscale Physics · Physics 2025-01-07 Maciej Matys , Atsushi Yamada , Toshihiro Ohki
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