Materials Selections and Growth Conditions for Large-Area, Multilayered, Visible Negative Index Metamaterials Formed by Nanotransfer Printing

2013 ◽  
Vol 2 (3) ◽  
pp. 256-261 ◽  
Author(s):  
Li Gao ◽  
Youngmin Kim ◽  
Abraham Vazquez-Guardado ◽  
Kazuki Shigeta ◽  
Steven Hartanto ◽  
...  
Keyword(s):  
Growth Conditions ◽  
Negative Index ◽  
Large Area

Growth of Large-Diameter CdZnTe and CdTeSe Boules for Hg1−xCdxTe Epitaxy: Status and Prospects

1989 ◽  
Vol 161 ◽  
Author(s):  
S. Sen ◽  
S.M. Johnson ◽  
J.A. Kiele ◽  
W.H. Konkel ◽  
J.E. Stannard
Keyword(s):  
Single Crystal ◽  
Defect Density ◽  
Large Diameter ◽  
Cylindrical Body ◽  
Growth Conditions ◽  
Grain Structure ◽  
Current Status ◽  
Conductive Heat ◽  
Large Area ◽  
Ir Detector

ABSTRACTSingle crystals of CdTe or dilute alloys of Cd1−yZnyTe (y ≤ 0.04) and CdTe1−zSez (z ≤ 0.04) with low defect density and large single-crystal area (>30 cm2) are required as substrates for high-quality epitaxial Hg1−xCdxTe thin films in the infrared (IR) detector industry. Bridgman or gradient freeze has been the most common current technique used for growing these materials. This paper reviews the current status and the evolution at SBRC of one variation of the Bridgman technique, viz., vertical-modified Bridgman (VMB), for producing large-area substrates with excellent uniformity and reproducibility. CdTe, Cd1−yZnyTe (y ≤ 0.04) and CdTe1−zSez (z ≤ 0.04) boules of 5-to 7.5-cm diameter have been grown unseeded in the present version of the VMB growth system. In general, under optimum growth conditions, the boules have the smallest grain structure (several grains) at the tip end with enhancement of grain selection as the cylindrical body of the boule is approached, resulting in one predominant and large grain occupying 70 to 80 percent of the entire boule volume; {111}-oriented Cd1−yZnyTe and CdTe1−zSez substrates with single-crystal areas as large as 50 to 60 cm2 have been obtained from these boules. Crystal quality characterized by x-ray rocking curve, IR transmission (2.5 to 20 µm), low-temperature photoluminescence, and Hall-effect measurements as a function of temperature, showed a strong correlation with the starting material quality (especially that of elemental Te and Se). Analyses of the thermal history during growth reveals that the presence of the ampoule (with charge) increases the temperature inside the furnace by 10 to 15 degrees. The temperature gradient at the tip was measured to be 8 to 10°C/cm and it dropped to 4 to 5°C/cm beyond 2.5 cm from the tip - where rapid enhancement of grain selection takes place in most boules. The effect of this temperature rise on the initial crystallization near the tip of a boule can be explained from the numerical thermal model that was developed for the growth process with radiative and conductive heat transfer included and using a temperature profile similar to that existing in the actual growth furnace. Conditions for maximizing the fraction solidifying with a slightly convex interface, hence maximizing the single-crystal yield are discussed.

Magnetic Properties and Microwave Loss of Polycrystalline M-Type Barium Hexaferrite Thick Films by Tape Casting

2014 ◽  
Vol 787 ◽  
pp. 322-325
Author(s):  
Da Ming Chen ◽  
Ying Li Liu ◽  
Yuan Xun Li ◽  
Jie Li ◽  
Huai Wu Zhang
Keyword(s):  
Millimeter Wave ◽  
Phase Shifter ◽  
Thick Films ◽  
Magnetic Hysteresis ◽  
Tape Casting ◽  
Hysteresis Loops ◽  
Barium Hexaferrite ◽  
Growth Conditions ◽  
Large Area ◽  
Microwave Loss

M-type barium hexaferrite (BaM) is a promising gyromagnetic material for self-biased microwave\millimeter wave devices because of its large uniaxial magnetocrystalline anisotropy and low microwave loss in high frequency. Due to the limitation of growth conditions, it is difficult to deposit BaM films with enough thickness by PLD, MBE and Magnetron Sputtering for practical application. However, it is demonstrated in present experiment that large area polycrystalline BaM thick films (500μm) with self-biasing (high remanence) and low microwave loss can be successfully fabricated by tape casting. X-ray diffraction and Scanning electron microscopy results indicate that these BaM thick films have highly c-axis oriented crystallographic texture with hexagonal morphology. Magnetic hysteresis loops reveal that samples exhibit excellent properties with a saturate magnetization (4πMs) of 3606G, a high squareness ratio (Mr/Ms) of 0.82. In addition, ferromagnetic resonance (FMR) measurement shows that the FMR linewidth is as small as 431Oe at 48GHz. These parameters ensure these BaM thick films are potentially useful for self-biased microwave\millimeter wave devices such as circulator, phase shifter and filter.

White beam X-ray Diffraction Topography (WBXDT) Studies of Bridgman Grown CdZnTe Crystals

2015 ◽  
Vol 1792 ◽  
Author(s):  
Stephen Babalola ◽  
Samuel Uba ◽  
Anwar Hossain ◽  
Giuseppe Camarda ◽  
Ralph James ◽  
...  
Keyword(s):  
Growth Parameters ◽  
Charge Trapping ◽  
Radiation Detectors ◽  
Growth Conditions ◽  
High Energy ◽  
Infrared Transmission ◽  
X Ray Diffraction ◽  
Large Area ◽  
X Ray ◽  
White Beam

ABSTRACTCZT is a semiconductor material that promises to be a good candidate for uncooled gamma radiation detectors. However, to date, we are yet to overcome the technological difficulties in production of large size, defect-free CZT crystals. The most common problem is accumulation of Tellurium precipitates as microscopic inclusions. These inclusions influence the charge collection through charge trapping and electric field distortion. We employed high energy transmission X-ray diffraction techniques to study the quality of the CdZnTe crystals grown by Bridgman Technique. Crystallinity and defects within two different growth set-ups, i.e. with and without choked seeding, were compared by imaging the crystal orientation topography with white beam X-ray diffraction topography (WBXDT). The X-ray diffraction topography results show high correlation with large-area infrared transmission images of the crystals. Grain boundaries that are highly decorated with Te inclusions are observed. Characteristic Te inclusion arrangements as a result of growth conditions are discussed. We also measured the electronic properties of the detectors fabricated from ingots grown using two Bridgman processes, and observed a reduction in electrical resistivity of choked-seeding-grown CdZnTe crystals. Our results show that although choked seeding technique holds a promise in the realization of high quality mono-crystalline CdZnTe, current growth parameters must be improved to obtain defect-free crystals. These results are helpful to attain optimal seeding process for Bridgman-growth of large single crystals of CdZnTe.

Microwave PECVD of Micro-Crystalline Silicon

2002 ◽  
Vol 715 ◽  
Author(s):  
Wim Soppe ◽  
Camile Devilee ◽  
Sacha Schiermeier ◽  
Harry Donker ◽  
J.K. Rath
Keyword(s):  
Large Scale ◽  
Gas Flow ◽  
Microwave Plasma ◽  
Crystalline Silicon ◽  
Plasma Source ◽  
Growth Conditions ◽  
Scale Production ◽  
Large Area ◽  
Deposition Rates ◽  
Microwave Source

AbstractThe deposition of micro-crystalline silicon by means of PECVD with a new linear microwave plasma source is investigated. This plasma source has successfully been introduced in the large scale production of multi-crystalline Si solar cells for the deposition of passivating silicon nitride layers. Advantages of this linear plasma source are the high deposition rates and the large area (up to 80 cm width, no length limitations) on which a homogeneous deposition can be achieved. Since this source has not been applied for deposition of micro-crystalline silicon before, we explored a large parameter space (substrate temperature, pressure, MW-power, gas flow rates), in order to find optimum growth conditions. It is observed that with this microwave source it is possible to grow micro-crystalline layers at significantly higher silane/hydrogen ratios and higher deposition rates than for conventional RF PECVD. In this paper, structural properties of the silicon layers, as investigated by Raman and FTIR spectroscopy, XRD and SEM measurements are discussed.

scholarly journals Antibacterial Nanostructured Ti Coatings by Magnetron Sputtering: From Laboratory Scales to Industrial Reactors

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1217 ◽  
Author(s):  
Alvarez ◽  
Muñoz-Piña ◽  
González ◽  
Izquierdo-Barba ◽  
Fernández-Martínez ◽  
...  
Keyword(s):  
Magnetron Sputtering ◽  
Growth Conditions ◽  
Bone Plate ◽  
Large Area ◽  
Laboratory Procedure ◽  
Small Areas ◽  
Laboratory Setup ◽  
Opposite Behavior ◽  
Laboratory Reactor

Based on an already tested laboratory procedure, a new magnetron sputtering methodology to simultaneously coat two-sides of large area implants (up to ~15 cm2) with Ti nanocolumns in industrial reactors has been developed. By analyzing the required growth conditions in a laboratory setup, a new geometry and methodology have been proposed and tested in a semi-industrial scale reactor. A bone plate (DePuy Synthes) and a pseudo-rectangular bone plate extracted from a patient were coated following the new methodology, obtaining that their osteoblast proliferation efficiency and antibacterial functionality were equivalent to the coatings grown in the laboratory reactor on small areas. In particular, two kinds of experiments were performed: Analysis of bacterial adhesion and biofilm formation, and osteoblasts–bacteria competitive in vitro growth scenarios. In all these cases, the coatings show an opposite behavior toward osteoblast and bacterial proliferation, demonstrating that the proposed methodology represents a valid approach for industrial production and practical application of nanostructured titanium coatings.

Low-Temperature Growth of Large Area, Vertically Aligned Carbon Nanotubes for Field Emission Applications

2005 ◽  
Vol 23 ◽  
pp. 297-300 ◽  
Author(s):  
Z.L. Tsakadze ◽  
K. Ostrikov ◽  
R. Storer ◽  
S. Xu
Keyword(s):  
Low Temperature ◽  
Field Emission ◽  
Control Strategies ◽  
Growth Conditions ◽  
Ni Catalyst ◽  
Large Area ◽  
Inductively Coupled ◽  
Chemical States ◽  
Vertically Aligned ◽  
Coupled Plasmas

Large area, highly uniform vertically aligned carbon nanotips (VACNTP) and other nanostructures have been grown on silicon (100) substrates with Ni catalyst in the low-temperature, lowfrequency, high-density inductively coupled plasmas (ICP) of methane-hydrogen-argon gas mixtures. The control strategies for the morphology, crystalline structure and chemical states of the resulting nanostructures by varying the growth conditions are proposed. XRD and Raman analyses confirm that the nanotips are well graphitized, which is favorable for the field emission applications.

scholarly journals Pulsed laser deposition of functional oxides - towards a transparent electronics

2014 ◽  
Vol 70 (a1) ◽  
pp. C1412-C1412
Author(s):  
Michael Lorenz
Keyword(s):  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
High Growth ◽  
Growth Conditions ◽  
High Growth Rate ◽  
Laser Deposition ◽  
Functional Oxides ◽  
Large Area ◽  
Bandgap Semiconductors ◽  
High Flexibility

Metal oxides, in particular with transition metals, show strong electronic correlations which determine a huge variety of electronic properties, together with other functionalities. For example, ZnO and Ga2O3 as wide-bandgap semiconductors have a high application potential as transparent functional layers in future oxide electronics [1-2]. Other oxides of current interest are ferrimagnetic spinels of the type MFe2O4 (M=Zn,Co,Ni), see K. Brachwitz et al. Appl. Phys. Lett. 102, 172104 (2013), or highly correlated iridate films, see M. Jenderka et al. Phys. Rev. B 88, 045111 (2013). Furthermore, combinations of ferroelectric and magnetic oxides in multiferroic composites and multilayers show promising magnetoelectric coupling. For the exploratory growth of the above mentioned novel oxides into nm-thin films, pulsed laser deposition (PLD) appears as the method of choice because of its extremely high flexibility in terms of material and growth conditions, high growth rate and excellent structural properties [3]. This talk highlights recent developments of new functional oxides using unique large-area PLD processes running for more than two decades in the lab of the author [3].

Nanoimprinting Techniques for Large-Area Three-Dimensional Negative Index Metamaterials with Operation in the Visible and Telecom Bands

ACS Nano ◽  
2014 ◽  
Vol 8 (6) ◽  
pp. 5535-5542 ◽  
Author(s):  
Li Gao ◽  
Kazuki Shigeta ◽  
Abraham Vazquez-Guardado ◽  
Christopher J. Progler ◽  
Gregory R. Bogart ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Negative Index ◽  
Large Area

Large-Area Deposition of GaAs by Mocvd

1989 ◽  
Vol 145 ◽  
Author(s):  
James T. Daly ◽  
Carson B. Roberts
Keyword(s):  
Growth Process ◽  
Large Scale ◽  
Computer Modelling ◽  
Growth Conditions ◽  
Large Area ◽  
Mocvd Reactor ◽  
Production Environments ◽  
Modelling Studies ◽  
Highly Uniform ◽  
Area Deposition

AbstractA new, large-scale, barrel-type MOCVD reactor which is capable of pro- ducing seven 3-inch wafers or fourteen 2-inch wafers at a time has been developed. Experiments and computer modelling studies of this geometry have been performed. The physical and electronic properties of n-type GaAs as a function of growth conditions are presented. Through the use of experimental design methods, the growth process has been optimized to yield highly uniform growth rates. The demonstrated uniformity supports the use of this reactor for production environments requiring 3-inch wafers.

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