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HF Solution (hf + solution)

Distribution by Scientific Domains
Physics and Astronomy66%

Selected Abstracts

Study of oscillatory behavior of open-circuit potential of silicon immersed in CuSO4/HF solutions

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2005
V. Parkhutik
Abstract This work studies the influence of experimental conditions on the occurrence and development of oscillations of the open-circuit potential (OCP) of silicon immersed in aqueous solution of 0.01 M CuSO4 + 0.06 M HF. The oscillations are very regular and last for days without any tendency to diminish. We show that they are quite sensitive to the temperature of the electrolyte, its viscosity, stirring, relative concentration of components, etc. We also present a phenomenological model to explain the oscillatory OCP behavior. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Fabrication of Large-Area Silicon Nanowire p,n Junction Diode Arrays,

ADVANCED MATERIALS, Issue 1 2004
K. Q. Peng
Large-area silicon nanowire p,n junction diode arrays (see Figure) have been fabricated by chemical etching of planar silicon p,n junction wafers in aqueous HF solution that contains appropriate amounts of silver nitrate near room temperature. The I,V characteristics have been measured using current-sensing atomic force microscopy, and nonlinear and rectifying electrical transport behavior has been observed. [source]

Broken symmetry approach and chemical susceptibility of carbon nanotubes

INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 8 2010
Elena F. Sheka
Abstract Constituting a part of odd electrons that are excluded from the covalent bonding, effectively unpaired electrons are posed by the singlet instability of the single-determinant broken spin-symmetry unrestricted Hartree,Fock (UBS HF) SCF solution. The correct determination of the total number of effectively unpaired electrons ND and its fraction on each NDÀ atom is well provided by the UBS HF solution. The NDÀ value is offered to be a quantifier of atomic chemical susceptibility (or equivalently, reactivity) thus highlighting targets that are the most favorable for addition reactions of any type. The approach is illustrated for two families involving fragments of arm-chair (n,n) and zigzag (m,0) single-walled nanotubes different by the length and end structure. Short and long tubes as well as tubes with capped end and open end, in the latter case, both hydrogen terminated and empty, are considered. Algorithms of the quantitative description of any length tubes are suggested. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010 [source]

High efficiency violet to blue light emission in porous SiC produced by anodic method

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 10 2010
T. Nishimura
Abstract Porous fluorescent (f-) SiC containing N and B was produced by anodic oxidation. The average crystal size can be controlled by adding K2S2O8 as an oxidant to dilute HF solution during the anodic process. With the reduction of the average crystal size of the porous crystal, the PL peak wavelength becomes shorter, and its intensity increases. Such behavior can be explained by the quantum size effect of donor-acceptor-pair recombination. Finally, we confirmed the superior fluorescent property of blue light emission in porous f-SiC crystal (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Wet chemical etching behavior of ,-Ga2O3 single crystal

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 9 2008
Shigeo Ohira
Abstract Wet chemical etching behavior of ,-Ga2O3 single crystal was investigated to evaluate its chemical stability and to explore etchants for ,-Ga2O3 single crystal. Undoped and Sn-doped ,-Ga2O3 single crystals were grown by the floating zone method, and (100)- and (001)-oriented samples were chemical-mechanical-polished to wafers. The samples were wet chemically etched in solutions such as HCl, H2SO4, HNO3, HF, H2O2:H2SO4:H2O=1:4:1, KOH, and NaOH. The samples were chemically stable against both acids and alkalis except HF and NaOH. Aqueous HF solution was found to etch ,-Ga2O3 uniformly at room temperature. The etch rate increased with increasing immersion time and HF content. Anisotropy of etch rate was observed between the (100) and (001) planes. The etch rate of Sn-doped ,-Ga2O3 was lower than that of undoped ,-Ga2O3, and the etch rate decreased with increasing Sn doping content. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Formation of porous layers on InSb(100) by anodization

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2003
P. Schmuki
Abstract The present work deals with anodization processes of n-type InSb(100). Preferential etching of InSb can be electrochemically initiated in HCl HBr and HF solutions. Except for etch features also the formation of porous layers can be observed. The resulting features were characterized by SEM and AES measurements. Due to the narrow bandgap of the material the results of the anodization process are neither sensitive to illumination of the n-type material nor to the doping level. The morphology of the attack depends strongly on the electrochemical conditions and the type of halogen acid present in the electrolyte. In HCl and HBr a black porous layer can be formed that is likely to consist to a certain extent of an antimony-oxo-chloride or antimony-oxo-bromide. In HF, however, polarization under a wide range of electrochemical conditions leads to a uniform etching of the InSb surface. [source]