Search results for "Gall"
showing 10 items of 903 documents
Structural investigation of crystallized Ge-Ga-Se chalcogenide glasses
2018
H. Klym thanks to the Ministry of Education and Science of Ukraine for support and Dr. P. Demchenko for the assistance in XRD experiments.
Investigation of Critical Points of Pore Formation Voltage on the Surface of Semiconductors of A3B5 Group
2021
In this work, critical values of pore-formation in electrochemical machining of semiconductors of A 3 B 5 group are studied. On the example of indium phosphide, the indicators of the series of dependence of current density on the voltage of anodization are studied. The rates of current density increase in the regime of gradual rise of anodization voltage are determined. According to these indicators, the intervals are established, within which the active pore-formation occurs on the surface of semiconductor.
Pulsed laser deposition of epitaxial yttrium iron garnet films with low Gilbert damping and bulk-like magnetization
2014
Yttrium iron garnet (YIG, Y [subscript 3]Fe[subscript 5]O[subscript 12]) films have been epitaxially grown on Gadolinium Gallium Garnet (GGG, Gd[subscript 3]Ga[subscript 5]O[subscript 12]) substrates with (100) orientation using pulsed laser deposition. The films were single-phase, epitaxial with the GGG substrate, and the root-mean-square surface roughness varied between 0.14 nm and 0.2 nm. Films with thicknesses ranging from 17 to 200 nm exhibited low coercivity (<2 Oe), near-bulk room temperature saturation moments (∼135 emu cm[superscript −3]), in-plane easy axis, and damping parameters as low as 2.2 × 10[superscript −4]. These high quality YIG thin films are useful in the investigation…
Density functional simulations of structure and polymorphism in Ga/Sb films.
2013
Thin films of gallium/antimony alloys are promising candidates for phase change memories requiring rapid crystallization at high crystallization temperatures. Prominent examples are the stoichiometric form GaSb and alloys near the eutectic composition GaSb(7), but little is known about their amorphous structures or the differences between the 'as-deposited' (AD) and 'melt-quenched' (MQ) forms. We have generated these structures using 528-atom density functional/molecular dynamics simulations, and we have studied in detail and compared structural parameters (pair distribution functions, structure factors, coordination numbers, bond and ring size distributions) and electronic properties (dens…
MOVPE growth of Ga 3D structures for fabrication of GaN materials
2004
Abstract This paper presents the growth and characterization of metallic gallium three-dimensional (3D) structures and preliminary results of their transformation into GaN-like structures. The structures were grown by metal-organic vapour phase epitaxy (MOVPE), using trimethyl gallium as gallium precursor on silicon (1 0 0). The growth temperature was between 550°C and 750°C. Interesting and new metallic structures were obtained with our growth parameters: balloon (montgolfier-like structure) and cauliflower-like. These metallic structures can grow up perpendicular to the substrate surface and have diameters between 0.1 and 5 μm, depending on the growth conditions. Moreover, selective metal…
Effects of the Buffer Layers on the Performances of (Al,Ga)N Ultraviolet Photodetectors
2004
The fabrication of (Al,Ga)N-based metal–semiconductor–metal (MSM) photovoltaic detectors requires the growth of high-quality (Al,Ga)N films. Inserting a low-temperature deposited buffer layer enables the growth of an epitaxial layer with a reduced density of defects. Two structures using GaN and AlN buffer layers have been deposited by low-pressure metalorganic chemical vapor deposition and used to fabricate MSM interdigitated detectors. The devices have been characterized to investigate the effects of the buffer layers on the detector performances.
Well-aligned hydrothermally synthesized zinc oxide nanorods on p-GaN without a seed layer
2015
Zinc oxide nanorods have great potential for the realization of high efficiency heterostructure LEDs based on pdoped gallium nitride. In order to obtain a good confinement of the light, a well-aligned nanorod waveguiding structure is desirable. This paper reports on the fabrication of vertical zinc oxide nanorods using a solution-based growth process that does not require a seed layer. The nanorods obtained follow the crystalline growth direction of the GaN layer along the c-axis. Various results with different reagent concentrations are reported.
Whispering gallery mode resonator and glucose oxidase based glucose biosensor
2020
Abstract In this research whispering gallery mode resonators (WGMRs) were applied in new concept of glucose sensor based on the shift of WGM resonance frequency induced by enzymatic oxidation of glucose by glucose oxidase (GOx), which was immobilized on WGM-resonator surface. During the enzymatic reaction catalyzed by GOx electrons from glucose via GOx are transferred towards co-immobilized gold nanoparticles (Au-NPs). WGM-resonators were fabricated from standard telecommunication optical-fiber melted in a hydrogen flame. Whispering gallery mode resonance based optical signals generated by these WGM-resonators were evaluated. These WGM-resonators, which were characterized by sufficient qual…
Dopant radial inhomogeneity in Mg-doped GaN nanowires
2018
International audience; Using atom probe tomography, it is demonstrated that Mg doping of GaN nanowires grown by Molecular Beam Epitaxy results in a marked radial inhomogeneity, namely a higher Mg content in the periphery of the nanowires. This spatial inhomogeneity is attributed to a preferential incorporation of Mg through the m-plane sidewalls of nanowires and is related to the formation of a Mg-rich surface which is stabilized by hydrogen. This is further supported by Raman spectroscopy experiments which give evidence of Mg-H complexes in the doped nanowires. A Mg doping mechanism such as this, specific to nanowires, may lead to higher levels of Mg doping than in layers, boosting the po…
Permanent photodoping of plasmonic gallium-ZnO nanocrystals
2020
This work was supported by the Latvian Council of Science in the framework of FLPP (Plasmonic oxide quantum dots for energy saving smart windows, lzp-2018/1-0187). Tanel Käämbre acknowledges financial support for the XPS instrumentation maintenance from the Estonian Centre of Excellence in Research project “Advanced materials and high- technology devices for sustainable energetics, sensorics and nanoelectronics” (TK141).