Zinc Single Crystals Research Articles

Sublimation of Cleaved Surface of Zinc Single Crystals. II. Interpretation and Discussion

Cleaved surfaces of zinc single crystals were sublimed. The fact that the sublimed layer thickness of 29 µm evaluated from the observed deposited thickness 0.3 µm of the film is almost equal to the depth of 22 µm of the recess engraved on the cleaved surface indicates the possibility of particle ejection. The sublimed mass 1.9 g evaluated from the Hertz-Knudsen formula with the evaporation coefficient α=1 is larger than the initial specimen mass of 0.57 g. The thickness, 34 µm, of the deposited film, estimated from the Hertz-Knudsen formula with α=1, is larger than the observed thickness of 0.3 µm. Scanning electron micrographs and evaluation of the sublimed mass and the film thickness indicate the inapplicability of the atomic evaporation theory.

Surface morphology and growth kinetics of zinc single crystals as influenced by vapour diffusion

The effect of diffusion in the vapour phase on both the surface morphology and growth kinetics of zinc single crystals growing in the presence of argon has been investigated. The shift of the basal face in the normal direction and the growth of the edge of that face as a function of time have been determined at constant temperature and supersaturation and at argon pressures within the range 5–250 Torr as well as in high vacuum of 1 × 10 −6 Torr. It has been found that the crystal size R and the edge length a change with time t following a linear law in the kinetic and a parabolic law in the diffusion regime respectively. The results obtained by kinetic investigations and morphological observations of the basal face are compared.

Climb of dislocation spirals and loops during room-temperature oxidation of zinc crystals

Dislocation spirals and loops are observed by Berg-Barrett X-ray topography in the basal cleaved zinc single crystals in the presence of large numbers of slip dislocations of all three basal Burgers vectors. Dislocation spirals and loops are often composed of bundles of these basal slip dislocations. The climb of dislocation spirals and loops, associated with vacancy injection into the lattice during oxidation, is also observed during the surface oxidation process at room temperature. The results imply that the oxidation process is closely related to and controlled by the lattice defect density and dislocation arrangements near the crystal surface.

Characterization of deep levels in zinc oxide

An electron trap of 0.3 eV depth was characterized in hydrothermally grown, single-crystal zinc oxide using deep-level transient spectroscopy. Specimens were fabricated with Ag Schottky contacts on (0001) surfaces. The capture cross section was determined to be 2.6×10−14 cm2. The defect is a native donor and is attributed to a singly ionized oxygen vacancy V•O.

Organometallic Vapor Phase Epitaxial Growth of ZnGeAs2 and (ZnGeAs2)xGe1−x on GaAs

ABSTRACTEpitaxial single crystal (001) chalcopyrite-structure ZnGeAs2 and single crystal (100) zinc blende-structure (ZnGeAs2)xGe1−x alloys have been grown by organometallic vapor phase epitaxy on (100) GaAs. Selected area electron diffraction was used to determine the crystal structure for several Zn:Ge molar flow ratios. Bulk chemical composition was determined by electron microprobe and correlated to crystal lattice constants obtained from x-ray diffraction. Due to the lattice mismatch between chalcopyrite-structure ZnGeAs2 and the GaAs substrate, the epitaxy is elastically strained, compressing the a-lattice constant and elongating the c-lattice constant. Optical absorption and transmission spectroscopy indicate the zinc-blende-structure material has an indirect band gap of approximately 0.6 eV, whereas the chalcopyrite ZnGeAs2 has a direct band gap of 1.15 eV. Secondary ion mass spectroscopy reveals significant Zn diffusion into the GaAs substrate if the Zn:Ge molar flow ratio exceeds the ratio required for stoichiometric chalcopyrite-structure crystal growth.

Sublimation of cleaved surfaces of zinc and galena single crystals I: Experimental

Cleaved surfaces of zinc and galena single crystals are sublimed. Scanning electron microscopy pictures of disintegrated surfaces and thin films deposited onto slides reveal that the surfaces are composed of conchoidal recesses about 1 μm in size or stepwise structure about 0.3 μm in size. Zinc films are formed by crystallites of nearly equal size (0.2 μm). The piled-up state of the crystallites suggests that they are ejected from the specimen surface.

Observation of vapour species concentration during the growth of single crystal zinc selenide films by molecular beam epitaxy

Work is in progress to produce single crystal layers of zinc sulphoselenide with accurately defined composition profiles for use in opto-electronic devices. The method of preparation being developed for the layers involves the controlled co-deposition of material from separate zinc selenide and zinc sulphide vapour sources. Layer composition will be controlled by computer from measurements made with a quadrupole mass spectrometer of the concentration of species in the vapour stream while the deposition of evaporant material is monitored with a quartz crystal microbalance. Preliminary results obtained with zinc selenide vaporised from a carbon crucible lead to the conclusion that zinc selenide does not exhibit congruent vaporisation as was initially expected. The composition of the evaporant stream is a function of both the vaporisation rate (source temperature) and the period of film deposition. Furthermore, it is found that measuring the concentration of zinc particles in the evaporant stream is complicated by the presence of a residual background of zinc vapour. Epitaxial layers of ZnSe grown on gallium arsenide substrates have been produced by the equipment. Examples of the structural and optical quality of the material obtained are presented.

Kinetics of Zinc Deposition on Zinc Single Crystals

The potential step method and scanning electron microscopy were used to investigate zinc deposition on zinc single crystals in high purity . Kinetics and morphology are dependent on crystal orientation. Below 20 mV layer type deposits are formed on the basal (0001) plane. Above 20 mV there is nucleation and growth of three dimensional centers. On the plane perpendicular to the basal plane (1120) only layer type growth was observed.

A temperature-dependent angular correlation study of positron annihilation in single crystal zinc

The angular correlation peak counts from positrons annihilating in single crystals of zinc have been measured from 95 to 660K in the (1010) and (0001) directions. A significant anisotropy has been observed between the counts in the two orientations which increases with temperature but in the opposite sense to a/c. The anisotropy increases near 290K, and then decreases to the nearly isotropic distribution of positrons trapped at vacancies. The vacancy formation energy, hf, determined by the threshold temperature of 403K, is 0.52+or-0.01 eV for both orientations. A trapping-model determination of hf is found to depend on the temperature dependence assumed in the saturation region; bet fits are obtained for hf=0.59+or-0.03 eV from the (0001) data, and 0.60+or-0.03 eV from the (1010) data. Full angular correlation curves have been measured at 95, 340 and 600K for both orientations. The effects of the higher momentum components in the positron wavefunction are calculated and could account for the anisotropy observed beyond the Fermi momentum at 95 and 340K. It is suggested that the temperature dependence of the peak counts anisotropy may arise from a relatively faster decline of the Fermi cut-off in the (1010) direction relative to (0001), as expected from the band structure of zinc.

The recovery of zinc after fast-neutron irradiation at low doses in liquid nitrogen

Abstract Yield-stress recovery of pure zinc single crystals has been investigated after fast-neutron irradiation of up to 3·4 × 1020 neutrons m−2 at liquid-nitrogen temperature. Three recovery stages were observed and the activation energy values associated with their main recovery peaks were determined. Stage III (80-140 K) shows an important recovery peak at 110 K with an associated activation energy of 0·31 eV. An activation energy of 0·50eV is associated with stage IV (140-175K). Stage V (above 175 K) shows a very important recovery peak at 210 K which is associated with an activation energy of 0·71 eV. Stage III is interpreted in terms of interstitial migration and stage IV is ascribed to vacancy migration. The recovery peak at 210 K in stage V is related to the annealing out of depleted zones.

Effect of Pressure on the Internal Friction in Zinc Single Crystals with Twins

Crystal Research and TechnologyVolume 21, Issue 6 p. K98-K100 Short Note Effect of Pressure on the Internal Friction in Zinc Single Crystals with Twins Dr. I. K. Nosolev, Dr. I. K. Nosolev Donetsk Physico-Technical Institute, Academy of Sciences of the Ukr. SSR, ul. Rozy Luksemburg, 72, Donetsk 340 114, USSRSearch for more papers by this authorDr. V. I. Zaytsev, Dr. V. I. Zaytsev Donetsk Physico-Technical Institute, Academy of Sciences of the Ukr. SSR, ul. Rozy Luksemburg, 72, Donetsk 340 114, USSRSearch for more papers by this authorDr. V. Ya. Platkov, Dr. V. Ya. Platkov Institute for Low Temperature Physics and Engineering, Academy of Sciences of the Ukr. SSR, Prospekt Lenina, 47, Kharkov 310 164, USSRSearch for more papers by this author Dr. I. K. Nosolev, Dr. I. K. Nosolev Donetsk Physico-Technical Institute, Academy of Sciences of the Ukr. SSR, ul. Rozy Luksemburg, 72, Donetsk 340 114, USSRSearch for more papers by this authorDr. V. I. Zaytsev, Dr. V. I. Zaytsev Donetsk Physico-Technical Institute, Academy of Sciences of the Ukr. SSR, ul. Rozy Luksemburg, 72, Donetsk 340 114, USSRSearch for more papers by this authorDr. V. Ya. Platkov, Dr. V. Ya. Platkov Institute for Low Temperature Physics and Engineering, Academy of Sciences of the Ukr. SSR, Prospekt Lenina, 47, Kharkov 310 164, USSRSearch for more papers by this author First published: June 1986 https://doi.org/10.1002/crat.2170210628AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume21, Issue6June 1986Pages K98-K100 RelatedInformation

Electrochemical etching

Silver faces with only a few exactly known dislocation emergence points were etched electrochemically. Deep pyramidal etch pits were observed on the screw dislocations whereas flat-bottomed pits arise on the edge dislocations. Qualitatively, this fact corresponds to the results obtained with natural, i.e. as-grown from the vapour phase, {0001}-faces of zinc single crystals. They were etched electrochemically by a new „droplet” technique. Quantitatively, the formation of two-dimensional negative nuclei during the etching of the edge-dislocation emergence points is understood as an atomistic process. Electrochemical etching of zinc was compared with chemical etching. It was concluded that SO4 selective adsorption (from ZnSO4 aqueous solution) changes significantly the polar diagram of the lateral dissolution rate on the basal face of the zinc single crystals and that the electrochemical etching reveals better the actual structure of these crystals.

Solution hardening of zinc crystals with aluminium and copper additions during the tensile test

Zinc single crystals, containing varying amounts of copper or aluminium, have been subjected to plastic deformation in the uni-axial tensile test in the temperature range of 173–473 K. The effect of the alloying additions and temperature on: initial forest dislocations density ρ f (0001), critical resolved shear stress (CRSS) value in the basal and pyramidal systems, twinning stress τ T value in the {10–12} 〈1̄011〉 systems has been tested. Photographs of the etch pits before and after plastic deformation of the single crystals tested have been presented.

High-pressure study of Rhodamine B in solution and adsorbed on oriented single-crystal zinc oxide

High-pressure study of Rhodamine B in solution and adsorbed on oriented single-crystal zinc oxide

Structure and conductivity of chloro(phthalocyaninato)zinc single crystals

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructure and conductivity of chloro(phthalocyaninato)zinc single crystalsMireille Mossoyan-Deneux, David Benlian, Marcel Pierrot, Andre Fournel, and Jean Pierre SorbierCite this: Inorg. Chem. 1985, 24, 12, 1878–1882Publication Date (Print):June 1, 1985Publication History Published online1 May 2002Published inissue 1 June 1985https://doi.org/10.1021/ic00206a036RIGHTS & PERMISSIONSArticle Views139Altmetric-Citations35LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (584 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

“Anomaly” of work-hardening coefficient in zinc single crystals

Basing on investigations of the mechanical properties at low temperatures and on TEM observations of dislocations, attempts have been made to explain the appearance of a minimum and maximum of the temperature dependence of the work-hardening coefficient in zinc and its alloys with Ag and Ga.

Further investigations of the magnetotransport properties of zinc

The authors study the transport coefficients of a zinc single crystal when a magnetic field is applied in a direction close to the c axis. For fields <or approximately=1.5 T they report a complete set of experiments and theoretical coefficients for a single crystal in the usual rectangular geometry with the emphasis being on the thermal and thermoelectric effects. The agreement between experimental and theory is usually good, though the model calculations are unable to produce sufficient harmonic content in the diagonal coefficients. The experimental data on the electrical resistivities have also been extended to high magnetic fields when the field is both parallel and close to the c axis. Generally speaking, these results are not understood and indicate that we are still ignorant of some of the basic physics appropriate to this situation.

The microstructural properties of sputtered zinc oxide SAW transducers

The microstructural properties of sputtered zinc oxide, ZnO, were investigated and related to their effective surface acoustic wave, SAW, transducer capabilities. SAW transducer films were fabricated on glass using different deposition parameters to produce different levels of transducer efficiency. The ZnO film microstructure was analysed using X-ray diffraction, surface profilometer and scanning electron microscope equipment. Etch techniques were used to further delineate the microstructural properties. The low coupling factor films had a low crystalline content, rougher surface topography and high etch rates. High coupling factor films were highly ordered, structurally dense, smooth surfaced films with etch properties characteristic of single crystal zinc oxide. The differences relate to growth conditions which produce a low defect density film structure of uniform polarity with a minimum of fibre grain inversions and weak intergrain boundaries Les proprietes microstructurales de l'oxyde de zinc pulverise sont etudiees et reliees a leur aptitude a la transduction piezoelectrique pour ondes de surface. Les films transducteurs a onde de surface sont deposes sur des supports en verre en faisant varier les conditions du depot de facon a atteindre differents degres d'efficacite de transduction. La microstructure du film de ZnO est analysee par diffraction X, profilometrie de surface et microscopie electronique a balayage. Des techniques de gravure sont egalement employees pour preciser les proprietes microstructurales

The Structural Properties of Sputtered Zinc Oxide

ABSTRACTX-ray diffraction, chemical etching and electron microscopy are useful in delineating the microstructural properties of c-axis normal oriented polycrystalline zinc oxide films, sputter deposited on amorphous substrates. Dense ZnO films with high crystalline content and low etch rates have a strong piezoelectric effect and low surface acoustic wave and guided optical wave propagation loss. The structural properties are dependent upon substrate conditions, deposition parameters and the type of sputtering system used. Scanning electron microscope examination of the surface and side fractures of high quality ZnO films show smooth continuous upper surface and side regions with no vertical fiber grain structures apparent. Light chemical etching reveals surface defects consisting of uniformly distributed conical shaped etch pit structures with a lateral to vertical etch ratio of 3 to 1. A correlation has been made between film structure and single crystal zinc oxide. The structural picture which emerges is that of a predominantly positive polarity (0001) upper surface layer with localized negative polarity (0001) fiber grain inversions. The sputter conditions which lead to low defect density films are a high substrate temperature, high deposition rate and low reactive gas pressures to promote the adatom mobility necessary for the preferred (0001) zinc face growth. Post deposition laser and thermal annealing can be used to reduce stress in the films and improve their guided optical wave properties.

Jump-like deformation and stability of the hardened and structural states of zinc single crystals with forest dislocations in the temperature range 293 to 4.2 K

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