Search results for "ta221"

Atomic layer deposition of AlN from AlCl3 using NH3 and Ar/NH3 plasma

2018

The atomic layer deposition (ALD) of AlN from AlCl3 was investigated using a thermal process with NH3 and a plasma-enhanced (PE)ALD process with Ar/NH3 plasma. The growth was limited in the thermal process by the low reactivity of NH3, and impractically long pulses were required to reach saturation. Despite the plasma activation, the growth per cycle in the PEALD process was lower than that in the thermal process (0.4A ° vs 0.7A ° ). However, the plasma process resulted in a lower concentration of impurities in the films compared to the thermal process. Both the thermal and plasma processes yielded crystalline films; however, the degree of crystallinity was higher in the plasma process. The…

Microscratch testing method for systematic evaluation of the adhesion of atomic layer deposited thin films on silicon

2016

The scratch test method is widely used for adhesion evaluation of thin films and coatings. Usual critical load criteria designed for scratch testing of coatings were not applicable to thin atomic layer deposition (ALD) films on silicon wafers. Thus, the bases for critical load evaluation were established and the critical loads suitable for ALD coating adhesion evaluation on silicon wafers were determined in this paper as LCSi1, LCSi2, LCALD1, and LCALD2, representing the failure points of the silicon substrate and the coating delamination points of the ALD coating. The adhesion performance of the ALD Al2O3, TiO2, TiN, and TaCN+Ru coatings with a thickness range between 20 and 600 nm and dep…

Kohn-Sham Decomposition in Real-Time Time-Dependent Density-Functional Theory An Efficient Tool for Analyzing Plasmonic Excitations

2017

The real-time-propagation formulation of time-dependent density-functional theory (RT-TDDFT) is an efficient method for modeling the optical response of molecules and nanoparticles. Compared to the widely adopted linear-response TDDFT approaches based on, e.g., the Casida equations, RT-TDDFT appears, however, lacking efficient analysis methods. This applies in particular to a decomposition of the response in the basis of the underlying single-electron states. In this work, we overcome this limitation by developing an analysis method for obtaining the Kohn-Sham electron-hole decomposition in RT-TDDFT. We demonstrate the equivalence between the developed method and the Casida approach by a be…

Review Article: Recommended reading list of early publications on atomic layer deposition—Outcome of the “Virtual Project on the History of ALD”

2017

Localized surface plasmon resonance in silver nanoparticles: Atomistic first-principles time-dependent density-functional theory calculations

2015

We observe using ab initio methods that localized surface plasmon resonances in icosahedral silver nanoparticles enter the asymptotic region already between diameters of 1 and 2 nm, converging close to the classical quasistatic limit around 3.4 eV. We base the observation on time-dependent density-functional theory simulations of the icosahedral silver clusters Ag$_{55}$ (1.06 nm), Ag$_{147}$ (1.60 nm), Ag$_{309}$ (2.14 nm), and Ag$_{561}$ (2.68 nm). The simulation method combines the adiabatic GLLB-SC exchange-correlation functional with real time propagation in an atomic orbital basis set using the projector-augmented wave method. The method has been implemented for the electron structure…

Structure and dielectric breakdown strength of nano calcium carbonate/polypropylene composites

2013

Nanodielectrics, a 21st-century phenomena, is envisioned to be the answer for material challenges in progressive high-voltage technology. It is well known that the proper dispersion of nanoparticles plays a key role in improving the dielectric properties of a material, but to understand where changes in the properties of a material originate, it is also essential to reveal the multiscale structure of the material. In this study, the dielectric permittivity, breakdown strength, and structure of nano calcium carbonate (nano-CaCO3)/polypropylene composites with 1.8-8.1 wt % doping were characterized systematically. The combined results from transmission electron microscopy, Raman microscopy, a…

Ray optics behavior of flux avalanche propagation in superconducting films

2015

Experimental evidence of wave properties of dendritic flux avalanches in superconducting films is reported. Using magneto-optical imaging the propagation of dendrites across boundaries between a bare NbN film and areas coated by a Cu layer was visualized, and it was found that the propagation is refracted in full quantitative agreement with Snell's law. For the studied film of 170 nm thickness and a $0.9\phantom{\rule{0.28em}{0ex}}\ensuremath{\mu}\mathrm{m}$ thick metal layer, the refractive index was close to $n=1.4$. The origin of the refraction is believed to be caused by the dendrites propagating as an electromagnetic shock wave, similar to damped modes considered previously for normal …

Normal-Metal–Insulator–Superconductor Tunnel Junction With Atomic-Layer-Deposited Titanium Nitride as Superconductor

2015

Vibrational Perturbations and Ligand–Layer Coupling in a Single Crystal of Au144(SC2H4Ph)60 Nanocluster

2015

We have determined vibrational signatures and optical gap of the Au144(PET)60 (PET: phenylethylthiol, SC2H4Ph) nanocluster solvated in deuterated dichloromethane (DCM-D2, CD2Cl2) and in a single crystal. For crystals, solid-state (13)C NMR and X-ray diffraction were also measured. A revised value of 2200 cm(-1) (0.27 eV) was obtained for the optical gap in both phases. The vibrational spectra of solvated AU144(PET)60 closely resembles that of neat PET, while the crystalline-state spectrum exhibits significant inhomogeneous spectral broadening, frequency shifts, intensity transfer between vibrational modes, and an increase in the overtone and combination transition intensities. Spectral broa…

Evidence of Weak Halogen Bonding: New Insights on Itraconazole and its Succinic Acid Cocrystal

2012

Exact knowledge of the crystal structure of drugs and lead compounds plays a significant role in the fields of crystal engineering, docking, computational modeling (drug–receptor interactions), and rational design of potent drugs in pharmaceutical chemistry. The succinic acid cocrystal of the systemic antifungal drug, itraconazole, reported by Remenar et al. (J. Am. Chem. Soc.2003, 125, 8456–8457) (CSD: IKEQEU), represents one of the classical examples displaying a molecular fitting mechanism in the solid state. In this work, we disclose the X-ray single-crystal structure of the cis-itraconazole–succinic acid (2:1) cocrystal and found that it differs slightly from the previously reported st…