Solid Solution Of Cd Research Articles

ОПТИЧНА СПЕКТРОСКОПІЯ ДЕТЕКТОРНИХ ВИСОКООМНИХ МОНОКРИСТАЛІВ CdTe (111) ТА ТВЕРДИХ РОЗЧИНІВ Cd 1-x Zn x Te (х= 0,1)

Cadmium telluride is used for the manufacture of uncooled gamma radiation detectors, and solid solutions of Cd 1-x Zn x Te (x=0.1) are used for the manufacture of X-ray and gamma radiation detectors. The study of the effect of doping on the physical properties of semiconductors is relevant both for experimenters and for the theoretical substantiation of physical processes. This paper presents the results of the study of optical reflection spectra in the spectral range (0,2-1,7) . 10 -6 m and transmittance in the region of the fundamental optical transition E 0 of high-resistivity CdTe single crystals of (111) orientation with resistivity ρ = (2÷5)·10 9 Ohm∙cm doped with chlorine, as well as solid solutions of Cd 1-x Zn x Te (x = 0.1) with resistivity ρ = (5 ÷30)∙10 9 Ohm∙cm. Since the optical reflection coefficient R = f (λ) is related to the optical transmittance T = f (λ) and absorption D = f (λ) by the ratio R+T+D=1 (with the light (electromagnetic) wave scattering in the studied samples not taken into account), the absorption spectra D=1-(R+T) versus the light (electromagnetic) wavelength λ were also constructed in this work. It is determined that the energy of the fundamental optical transition E 0 of the studied materials at T = 300 K is as follows: for CdTe - 1.44 eV; and for Cd 1-х Zn х Te (x = 0.1) - 1.5 eV. The energy relaxation time of free charge carriers τ for p-CdTe (111) single crystals and Cd 1-х Zn х Te (x = 0.1) solid solutions was estimated to be 1.343-10 -14 s and 0,878·10 -14 s, respectively. The effective "optical" mobility for single crystals of p-CdTe (111) and solid solutions of Cd 1-х Zn х Te (x = 0.1) is 274 . 10 -4 ; 179,5 . 10 -4 , respectively. It has been shown that the investigated crystals are of high (detector) quality, which is crucial for the manufacture of highly sensitive and high-resolution ionising radiation sensors. The practical value of the obtained results lies in the determination of electronic and physical parameters of technically important semiconductors CdTe and Cd 1-х Zn х Te (x=0.1).

Phase equilibria in the neodymium–cadmium binary system

The equilibrium phase diagram of the neodymium–cadmium system has been established by thermal, metallographic and X-ray analysis based on a study of 70 alloys. The system contains three congruently melting intermetallic compounds, i.e. NdCd (1040°C), NdCd2 (995°C), Nd11Cd45 (855°C), and four incongruently melting compounds NdCd3 (860°C), Nd13Cd58 (740°C), NdCd6 (655°C) and NdCd11 (520°C). Four eutectic reactions are found in this binary system, i.e. at ∼25at.% Cd and 770°C, at 58at.% Cd and 955°C, at 79at.% Cd and 850°C, and very close to pure Cd at 318°C, as well as one eutectoid reaction at ∼15at.% Cd and 500°C. The solid solubility of Nd in Cd is negligible. Dilatometric curves were recorded for three Nd–Cd compositions up to 4at.% Cd, to accurately determine phase transitions between the solid solutions of Cd in the low- and high-temperature modification of Nd.

Combined adsorption of ammonia and oxygen on the surface of solid solutions of Cd x Hg1 − x Te

The adsorption of ammonia, oxygen, and the NH3 + O2 mixture on solid solutions CdxHg1 − xTe is studied. The low adsorbability of the mixture, as compared to that of the individual components, is established. Conclusions are drawn as to the nature of its active centers. Schemes for the combined adsorption of ammonia and oxygen are proposed. The temperature areas of tentatively highest catalytic activity of CdTe and CdHgTe in the reaction of ammonia oxidation are established. The formation of gaseous nitrogen in the final products is demonstrated. The degree of ammonia’s transformation into nitrogen is 97–99%. It increased with a rise in temperature and did not depend on the initial ammonia concentration.

Microstructure and Characteristics of Interfacial Region in Soldering Joint of ZA Alloy

Analytical instruments such as optical microscope, SEM and TEM are employed to investigate and analyze the microstructure and characteristics of soldering joint interfacial region. The results indicated that interactive crystallization exists in part of the interfacial region by using a newly developed kind of soldering filler metal. The composition of the interfacial region is complex such that both solid solution of Cd,Sn,Zn and small amounts of fine grained compounds of Mg2Sn,MgZn exist. Solid solution can improve the strength and plasticity, and small amounts of fine-grained compounds can strengthen the matrix which is beneficial for improving the bonding strength. However, successive laminate structure of intermetallic compounds will result in embitterment and deteriorate the properties of the joint.

Comparison of Different Content of Cd and Sb Element on the Microstructure, Mechanical Properties of As-Cast AZ31 Magnesium Alloy

The effect of Cd and Sb addition on the microstructural and mechanical properties of as-cast AZ31 alloys was investigated and compared. The results indicate that the difference of Sb and Cd in the microstructure and mechanical properties of as-cast AZ31 magnesium alloy is significant. Addition of 0.15%Sb (mass fraction) to AZ31 alloy can refine the matrix and β-Mg17Al12phase but not form a new phase Mg3Sb2. Oppositely, by addition of 0.3-0.7% Cd to AZ31 alloy, Cd was dissolved into the AZ31 alloy, the phase composition did not change but was refined also. Accordingly, the Cd-refined AZ31 alloy exhibits higher tensile and impact toughness and Brinell hardness properties than the Sb- refined one. The difference of Sb and Cd in the mechanical properties is possibly related to the solid solution of Cd into the matrix and formation of Mg3Sb2which has the same close-packed hexagonal structure as α-Mg.

Cd1−xZnxO [0.05 ≤x≤ 0.26] synthesized by vapor-diffusion induced hydrolysis and co-nucleation from aqueous metal salt solutions

Nanoparticulate Cd(1-x)Zn(x)O (x = 0, 0.05-0.26, 1) is synthesized in a simple two-step synthesis approach. Vapor-diffusion induced catalytic hydrolysis of two molecular precursors at low temperature induces co-nucleation and polycondensation to produce bimetallic layered hydroxide salts (M = Cd, Zn) as precursor materials which are subsequently converted to Cd(1-x)Zn(x)O at 400 °C. Unlike ternary materials prepared by standard co-precipitation procedures, all products presented here containing < 30 mol% Zn(2+) ions are homogeneous in elemental composition on the micrometre scale. This measured compositional homogeneity within the samples, as determined by energy dispersive spectroscopy and inductively coupled plasma spectroscopy, is a testimony to the kinetic control achieved by employing slow hydrolysis conditions. In agreement with this observation, the optical properties of the materials obey Vegard's Law for a homogeneous solid solution of Cd(1-x)Zn(x)O, where x corresponds to the values determined by inductively coupled plasma analysis, even though powder X-ray diffraction shows phase separation into a cubic mixed metal oxide phase and a hexagonal ZnO phase at all doping levels.

High-pressure behavior of CdSb: Compound decomposition, phase formation, and amorphization

High pressure study of the binary CdSb compound reveal several phase transitions including compound decomposition, phase formation, and amorphization on decompression. Above $7.3\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$ a simple hexagonal (sh) phase of composition ${\mathrm{Cd}}_{44}{\mathrm{Sb}}_{56}$ and an excess of pure Cd are observed. Above $20\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$ after heating at $423\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, the material decomposes into nearly pure components, hcp-Cd and Sb-II. Above $40\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$, a bcc phase (solid solution of Cd in bcc-Sb) is observed together with an additional intermediate phase. Amorphization of CdSb occurs on decompression after decomposition into the sh phase and Cd. Structural properties of the amorphous phase in the Cd-Sb system are compared with those of the known amorphous semiconductors and discussed in terms of Fermi sphere---Brillouin zone interactions.

Band structure-controlled solid solution of [formula omitted][formula omitted] photocatalyst for hydrogen production by water splitting

A series of Cd 1 - x Zn x S ( x = 0 –0.92) photocatalysts were prepared by coprecipitation method and were calcined at 723 K under N 2 atmosphere. X-ray diffraction patterns results showed that the solid solution of Cd 1 - x Zn x S were formed between ZnS and CdS. UV–Vis spectra indicated that the absorption edges of Cd 1 - x Zn x S were red-shifted as the value of x decreased. The band gaps of the photocatalysts were estimated to be between 2.20–3.12 eV ( x = 0 –0.92) from the onsets of the absorption edges and almost showed linear variation with x increasing. The position of conduction band for solid solution is shifted towards more negative potential as compared to that of CdS. The hydrogen productions of Cd 1 - x Zn x S ( x = 0 –0.92) by splitting water photocatalytically under ultraviolet and visible light irradiation were carried out in an inner-irradiation type reactor. The results indicated that the photocatalyst of Cd 0.62 Zn 0.16 S has the highest rate of hydrogen evolution with the quantum efficiency of 2.17% and 0.60% under ultraviolet and visible light irradiation, respectively. It has been considered that the crystallite size, (1 0 1) plane and band gap for the Cd 1 - x Zn x S solid solutions have a strong influence on the efficiency of hydrogen production capability for water splitting.

High-pressure synthesis, crystal structures, and characterization of CdVO 3−δ and solid solutions CdVO 3–NaVO 3

CdVO 3− δ and solid solutions of Cd 1− x Na x VO 3 with the GdFeO 3-type perovskite structure were prepared using a high-pressure (6 GPa) and high-temperature technique. No significant oxygen and cation deficiency was found in CdVO 3. Cd 1− x Na x VO 3 are formed in the compositional range of 0 ⩽ x ⩽ 0.2 . CdVO 3 and Cd 1− x Na x VO 3 demonstrate metallic conductivity and Pauli paramagnetism between 2 and 300 K. A large electronic contribution to the specific heat ( γ = 13.4 and 11.2 mJ / ( mol K 2 ) for CdVO 3 and Cd 0.8Na 0.2VO 3, respectively) was observed at low temperatures due to the strongly correlated electrons. Crystal structures of CdVO 3 and Cd 0.8Na 0.2VO 3 were refined by X-ray powder diffraction: space group Pnma; Z = 4 ; a = 5.33435 ( 7 ) Å , b = 7.52320 ( 9 ) Å , and c = 5.26394 ( 6 ) Å for CdVO 3 and a = 5.32056 ( 9 ) Å , b = 7.50289 ( 13 ) Å , and c = 5.25902 ( 8 ) Å for Cd 0.8Na 0.2VO 3.

ChemInform Abstract: Solid Solution of CdyZn1‐yS Nanosized Particles: Photophysical Properties.

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Novel optical features in Cd + ion-implanted LEC-grown GaAs

High-energy Cd + ions were implanted into undoped GaAs grown by the liquid encapsulated Czochralski (LEC) method for a wide Cd concentration, [Cd] between 1 × 10 16 and 3 × 10 21 cm −3. Raman scattering spectra indicate that for [Cd] lower than 1.7 × 10 18 cm −3, the damage induced by high-energy ion-implantation can be eliminated by high-temperature annealing. For [Cd] higher than 3 × 10 18 cm −3, the intensity of the LO-phonon mode gradually reduces and its width significantly broadens with increasing [Cd]. For [Cd] = 1 × 10 21 and 3 × 10 21cm −3, a forbidden mode appears on the lower-frequency side of the LO-phonon mode. The results of Rutherford backscattering spectrometry (RBS), and Hall-effect measurements suggest that a solid solution of Cd in GaAs is formed in this high-concentration region. 2 K photoluminescence (PL) spectra indicate that four emissions related with acceptor-acceptor pairs, [g-g], [g-g] 2, [g-g] 3, and [g-g] β are formed in the near band-edge region even by using LEC-GaAs as a substrate. In the energy region far below the band-edge, many emissions associated with vacancies and complexes with doped Cd atoms are produced specifically for high [Cd].

Phase stability investigations of the palladium-cadmium system: part i. thermodynamic studies

The vapor pressure of cadmium in palladium-cadmium alloys was determined between 830 and 1350 K and between 33 and 65 at. pct Cd by two different isopiestic methods. An analysis of the resulting partial molar quantities of Cd in the β1-phase in terms of Chang's theoretical model for the Ll0-structure yielded a disorder parameter α= 7 × 10-4 and a second-nearest neighbor parameter η = 0.75 at 1073 K. Available literature data for the thermodynamic activities of Cd in the α-phase (solid solution of Cd in Pd) were evaluated using a subregular solution model. By combining these values with the present experimental data, all relevant partial and integral thermodynamic properties for the α- and β1-phase could be derived. At the stoichiometric composition of the β1-phase, values of ΔG = -38.0 kJ(g-atom)-1 and ΔH = -53.7 kJ(g-atom)-1, referred to Pd(s) and Cd(l), were obtained for a temperature of 1073 K.