scholarly journals Kinetic Control of Catalytic CVD for High-Quality Graphene at Low Temperatures

ACS Nano ◽  
2012 ◽  
Vol 6 (11) ◽  
pp. 9996-10003 ◽  
Author(s):  
Robert S. Weatherup ◽  
Bruno Dlubak ◽  
Stephan Hofmann
Keyword(s):  
Low Temperatures ◽  
Kinetic Control ◽  
High Quality ◽  
Catalytic Cvd

Highly efficient planar perovskite solar cells achieved by simultaneous defect engineering and formation kinetic control

2018 ◽  
Vol 6 (46) ◽  
pp. 23865-23874 ◽  
Author(s):  
Jiaqi Cheng ◽  
Hong Zhang ◽  
Shaoqing Zhang ◽  
Dan Ouyang ◽  
Zhanfeng Huang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Low Temperature ◽  
Power Conversion Efficiency ◽  
Power Conversion ◽  
Perovskite Solar Cells ◽  
Precursor Solution ◽  
Kinetic Control ◽  
Defect Engineering ◽  
High Quality ◽  
Formation Kinetic

Incorporation of non-fullerene acceptor into perovskite precursor solution is demonstrated to form high-quality perovskite films with low defect concentrations. The power conversion efficiency of low-temperature processed perovskite solar cells is improved up to 20.10%.

Low-temperature Preparation of Crystallized Zirconia Films by ECR Plasma MOCVD

2005 ◽  
Vol 890 ◽  
Author(s):  
Hiroshi Masumoto ◽  
Takashi Goto
Keyword(s):  
Magnetic Field ◽  
Low Temperature ◽  
Low Temperatures ◽  
Monoclinic Zirconia ◽  
High Quality ◽  
Ion Chamber ◽  
Ecr Plasma ◽  
Low Temperature Preparation ◽  
Oxide Ion ◽  
Zirconia Films

ABSTRACTIt is known that zirconia has excellent thermal and chemical stability, and oxide ion conduction. Therefore, YSZ is expected to be used as oxide ion conducting materials, optical mirror materials, catalytic materials and heat-resistant materials. Zirconia films have been fabricated by PVD (ex. sputtering and laser-ablation), chemical vapor deposition (CVD) and sol-gel methods. CVD is capable to prepare high quality zirconia films with excellent conformal coverage; however, deposition temperature of conventional CVD was usually high than PVD. On the other hand, an electron cyclotron resonance (ECR) plasma is high-activity plasma and high quality crystalline films can be obtained at low temperature by using ECR plasma. In the present study, zirconia thin films were prepared at low temperatures on quartz, polycarbonate and polyimide substrates by ECR plasma MOCVD.Zr-hexafluoroacetylacetonato solution was used as a precursor. The source, which was placed in a glass bubbler, was carried into a reactor by Ar gas. A microwave (2.45 GHz, 500 W) was introduced into the ion chamber through a rectangular wave guide. A magnetic field (875 Gauss) was applied to the ion chamber to satisfy the ECR condition. A mirror-type magnetic field (450 Gauss at the substrate stage) was applied in order to raise a plasma density, which results in an increase of the deposition rates of films. Substrate temperature (Ts) was from 30 to 700 C by water-cooling holder and infrared lamp heater. Microwave power was changed from 0 to 900 W. The deposition time was from 30 to 120 minutes.Cubic, monoclinic and tetragonal zirconia films were obtained over Ts=400 C, and cubic and monoclinic zirconia films were obtained below Ts= C. Cubic and monoclinic zirconia films were also obtained at no heating. The deposition rate increased from 10 to 20 nm/min with increasing Ts from no heating to 600 C. Crystallized zirconia films were obtained on polycarbonate and polyimide substrates at no heating. The ECR plasma was significantly effective to prepare crystallized zirconia films at low temperatures.

Dielectric Loss in Li- and Na-Swept α-Quartz and the Effect of Irradiation

1983 ◽  
Vol 24 ◽  
Author(s):  
J. Toulouse ◽  
A.S. Nowick
Keyword(s):  
Dielectric Loss ◽  
Low Temperature ◽  
Low Temperatures ◽  
Quantum Effects ◽  
Frequency Stability ◽  
Distorted Tetrahedron ◽  
High Quality ◽  
Quartz Crystals ◽  
Alkali Ions ◽  
Synthetic Crystals

ABSTRACTAlkali ions, which compensate for substitional Al3+, play an important role in the frequency stability of α-quartz crystals. In this work, low temperature dielectricloss measurements (between 2.9 and 300 K) are carried out on crystals that have been “swept” so as to introduce either Li+ or Na+. High quality synthetic crystals as well as natural crystals are employed. The well known loss peaks due to Al-Na pairs are further explored and similar peaks due to Al-Li are sought after but not found. It is concluded that the Al-Li pair is oriented along the C2 -axis of the A104 distorted tetrahedron. After irradiation, large peaks are observed at very low temperatures both in Li+- and Na+-containing crystals. These peaks, which are distorted below ∼6 K due to the onset of quantum effects, may originate in alkali centers produced when alkali ions are liberated by the irradiation.

TEM Study of the Morphology Of GaN/SiC (0001) Grown at Various Temperatures by MBE

1999 ◽  
Vol 595 ◽  
Author(s):  
W.L. Sarney ◽  
L. Salamanca-Riba ◽  
V. Ramachandran ◽  
R.M Feenstra ◽  
D.W. Greve
Keyword(s):  
Low Temperatures ◽  
Stacking Faults ◽  
Full Width ◽  
X Ray Diffraction ◽  
High Quality ◽  
Double Crystal ◽  
Tem Analysis ◽  
Rocking Curve ◽  
X Ray ◽  
Substrate Temperatures

AbstractGaN films grown on SiC (0001) by MBE at various substrate temperatures (600° - 750° C) were characterized by RHEED, STM, x-ray diffraction, AFM and TEM. This work focuses on the TEM analysis of the films' features, such as stacking faults and dislocations, which are related to the substrate temperature. There are several basal plane stacking faults in the form of cubic inclusions for samples grown at low temperatures compared to those grown at high temperatures. The dislocation density is greatest for the film grown at 600°C, and it steadily decreases with increasing growth temperatures. Despite the presence of various defects, x-ray analysis shows that the GaN films are of high quality. The double crystal rocking curve full width at half maximum (FWHM) for the GaN (0002) peak is less than 2 arc-minutes for all of the films we measured and it decreases with increasing growth temperature.

High-quality epitaxial Si growth at low temperatures by atmospheric pressure plasma CVD

2008 ◽  
Vol 517 (1) ◽  
pp. 242-244 ◽  
Author(s):  
K. Yasutake ◽  
H. Ohmi ◽  
Y. Kirihata ◽  
H. Kakiuchi
Keyword(s):  
Atmospheric Pressure ◽  
Low Temperatures ◽  
Atmospheric Pressure Plasma ◽  
Plasma Cvd ◽  
High Quality ◽  
Pressure Plasma

High speed deposition of high‐quality ferrite films from aqueous solution at low temperatures (≤90 °C)

1987 ◽  
Vol 61 (8) ◽  
pp. 3211-3213 ◽  
Author(s):  
M. Abe ◽  
Y. Tamaura ◽  
Y. Goto ◽  
N. Kitamura ◽  
M. Gomi
Keyword(s):  
Aqueous Solution ◽  
Low Temperatures ◽  
High Speed ◽  
High Quality ◽  
Ferrite Films

Film Growth, by Seeded Supersonic Beams, of Thiophene-Based Oligomers with Controlled Optical, Structural and Morphological Properties

1999 ◽  
Vol 598 ◽  
Author(s):  
Tullio Toccoli ◽  
Maurizio Ferrari ◽  
Sabina Ronchin ◽  
Alessandro Podestà ◽  
Paolo Milani ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Molecular Beam ◽  
Film Growth ◽  
Morphological Properties ◽  
Published Data ◽  
Film Properties ◽  
High Quality ◽  
Supersonic Molecular Beam ◽  
Supersonic Beams ◽  
Novel Approach

ABSTRACTA novel approach for the deposition of high quality films of oligothiophenes has been developed. It is based on an original seeded supersonic molecular beam combined with a UHV deposition chamber. This method gives an unprecedented control on film properties. Several T4 films under different beams conditions have been prepared and characterized by optical absorption, photoluminescence and TMAFM. Morphology, structure and optical response are controlled by the beam's parameters. Highly ordered films, up to several hundreds of nm thick, show well resolved vibronic structures in low temperatures PL as only the best published data on films a few monolayers thick do.

Polarized Raman Scattering Study of ZnGeP2 Single Crystals

1997 ◽  
Vol 484 ◽  
Author(s):  
Spirit Tlali ◽  
Howard E. Jackson ◽  
M. C. Ohmer ◽  
P. G. Schunemann ◽  
T. M. Pollak
Keyword(s):  
Raman Scattering ◽  
Single Crystals ◽  
Raman Spectra ◽  
Low Temperatures ◽  
High Quality ◽  
Crystal Orientations ◽  
Gradient Technique ◽  
Theoretical Predictions ◽  
Scattering Study ◽  
Polarized Raman

AbstractRaman scattering experiments on high quality ZnGeP2 single crystals grown by the seeded horizontal dynamic gradient technique have been carried out. Polarized Raman spectra were obtained in the backscattering geometry at both room and low temperatures for several crystal orientations and compared with group theoretical predictions. Raman spectra from as-grown and annealed samples display distinctive differences which were explored by utilizing two different excitation wavelengths: 514.3 nm and 632.8 nm; the observed differences are attributed to a surface interdiffuasion effect.

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