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The primary goal of this paper is to study a few advantages of bulk nanoparticles of Cu-doped SnO2 using the solid-state reaction method. Many innovative methods were employed to evaluate the special tuning of the bandgap and other structural and morphological properties of the material. X-ray diffractometer (XRD) confirmed that tin oxide has a rutile-type tetragonal-shaped structure with space group P42 / mnm. The average crystallite size was calculated which was found to increase from 53 to 80 nm by increasing the Cu-doping from x = 0 to x = 0.30. SEM images specified that nanoparticles are inhomogeneous and densely close to each other and the average particle size was found to be in the range of ~225–430 nm. Transmission electron microscopy (TEM) images showed the grains present in a few cubic and spherical shapes and grain size was increased (~20–90 nm) with doping of copper in the SnO2 lattice. UV–Vis spectroscopy showed that the band gap increased from 3.531 to 3.701 eV for pure SnO2 and Cu-doped SnO2, respectively. XPS identified the electronic state of Sn as well as Cu atoms as 4 + and 2 + , respectively. Raman spectroscopy showed that only three vibrational modes, i.e., A1g, B2g and doubly degenerate Eg, exist in a sample. [ABSTRACT FROM AUTHOR]

The primary goal of this paper is to study a few advantages of bulk nanoparticles of Cu-doped SnO2 using the solid-state reaction method. Many innovative methods were employed to evaluate the special tuning of the bandgap and other structural and morphological properties of the material. X-ray diffractometer (XRD) confirmed that tin oxide has a rutile-type tetragonal-shaped structure with space group P42 / mnm. The average crystallite size was calculated which was found to increase from 53 to 80 nm by increasing the Cu-doping from x = 0 to x = 0.30. SEM images specified that nanoparticles are inhomogeneous and densely close to each other and the average particle size was found to be in the range of ~225–430 nm. Transmission electron microscopy (TEM) images showed the grains present in a few cubic and spherical shapes and grain size was increased (~20–90 nm) with doping of copper in the SnO2 lattice. UV–Vis spectroscopy showed that the band gap increased from 3.531 to 3.701 eV for pure SnO2 and Cu-doped SnO2, respectively. XPS identified the electronic state of Sn as well as Cu atoms as 4 + and 2 + , respectively. Raman spectroscopy showed that only three vibrational modes, i.e., A1g, B2g and doubly degenerate Eg, exist in a sample. [ABSTRACT FROM AUTHOR]

Using a quantum hydrodynamic model, quantum effects (via Bohm potential) on modulational amplification in ion-implanted semiconductor magnetoplasmas are investigated. Expressions are obtained for the threshold pump amplitude and the growth rate of modulated beam for both the electrons and implanted colloids. Numerical analysis is performed for n-InSb/CO2 laser system. The dependence of the threshold pump amplitude and the growth rate of modulated beam for electrons on wave number, applied magnetic field (via electron cyclotron frequency) and electron concentration (via electron-plasma frequency) and the dependence of the threshold pump amplitude and the growth rate of modulated beam for implanted colloids on wave number and colloid concentration (via colloid-plasma frequency) are explored. The lowering in threshold pump amplitude and enhancement of the growth rate of modulated beam for both the electrons and implanted colloids are observed by incorporating the quantum effects. The analysis provides detailed information of quantum effects on modulational amplification in ion-implanted semiconductor magnetoplasmas composed of electrons and negatively charged implanted colloids and establishes the technological potentiality of chosen samples as the hosts for the fabrication of efficient optical modulators. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we report the first ever experimental Compton profile study of WS2 and WSe2 employing 20 Ci 137Cs Compton spectrometer. To interpret our experimental data, the electronic properties of these compounds have been determined by linear combination of atomic orbitals, full potential linearised augmented plane-wave and spin polarised relativistic Korringa–Kohn–Rostoker (SPR-KKR) schemes. The band structure calculations show that both the WS2 and WSe2 are indirect-gap semiconductors. The SPR-KKR calculations are found to be relatively in poor agreement with the experimental electron momentum densities. The relative nature of bonding in both the dichalcogenides is explained in terms of equal-valence-electron-density profiles, Mulliken''s population and valence band charge densities. [Copyright &y& Elsevier]

Applying three different sophisticated growth methods using MBE we succeeded in growing unburied and buried quantum-dot structures of HgSe:Fe on a ZnSe/GaAs buffer/substrate system in (0 0 1) orientation. For the buried quantum dots the buffer/substrate system was specially prepared by a thermal desorption process resulting in the generation of surface dips acting as a mould for the quantum dots. The advantage of this method lies in the possibility of easily removing the wetting layer without affecting the dots. In this way the usually strong influence of the wetting layer in the experimental data for the highly conductive HgSe:Fe could nearly completely be suppressed. The growth process was in situ controlled by RHEED providing detailed information on the structural properties. The ex situ structural investigation used AFM and SEM. The characterization of the electronic properties was performed by IR megagauss-magneto spectroscopy. [Copyright &y& Elsevier]

We report effect of external ac-field on photorefractive properties of CdTe:Ge at 1.06 μm. Phenomena related to excitation of the space-charge waves (SCW) of traps recharging, such as spatial subharmonics generation and resonant two-beam coupling, are studied. Dramatic enhancement of the photorefractive response is achieved in ac-biased crystal by adjustment of recording conditions (field and grating spacing) to eigen resonance related to excitation of the space charge waves. [Copyright &y& Elsevier]

Modification of ternary Hg1-xCdxTe alloys with 0.21≤x≤0.55 and quaternary Hg1-y-zZnyCdzTe alloys by treatment with low-energy (E<800 eV) Ar ions was studied. It is shown that for conductivity type conversion in Hg1-xCdxTe with 0.28≤x≤0.39, it is essential to use a neutralised ion beam. The observed dependence of the conversion depth on x agrees with the diffusion conversion model. The effect of self-compensation of intrinsic acceptor defects by intrinsic donors during the annealing prior to ion treatment is confirmed. This effect provides the possibility of controlling the carrier concentration in the n-region of p–n junctions fabricated by ion-beam treatment in vacancy-doped Hg1-xCdxTe. [Copyright &y& Elsevier]

Magneto-transport and transmission data on Hg(Mn)Se–Fe semiconductor structures in high magnetic fields up to the multi-megagauss range are presented. The magnetic fields were generated either by conventional DC-superconducting solenoids, nondestructive solenoids in pulsed operation up to 40 T, single-turn coil technique up to 140 T, or explosive flux compression up to 450 T. The samples investigated range from 3D systems in bulk, 2D in quantum wells, 1D in self-organized quantum wires, and 0D in quantum dots. The semiconductor structures of low dimensionality were grown by MBE. The different experimental results are compared with theoretical concepts. [Copyright &y& Elsevier]

This work reports results concerning the effect of the deposition parameters on the structural properties of Cu2ZnSnSe4 thin films, grown through a chemical reaction of the metallic precursors via coevaporation in a three-stage process. X-ray diffraction measurements revealed that the samples deposited by selenization of Cu and Sn grow in the Cu2Se and SnSe2 phases, respectively. The effect of deposition temperature and Cu/Se mass ratio on the transport properties of Cu2ZnSnSe4 films was analyzed. The electrical behavior of the compound was studied. [ABSTRACT FROM AUTHOR]

Aluminum nitride (AlN) thin films were deposited by reactive radio frequency magnetron sputtering from pure aluminum target, onto Si (100), ultra dense flat carbon, and quartz. Series of samples were obtained varying the Ar and N2 gaseous mixture. The characterizations performed were Fourier transform infrared (FTIR), X-ray diffraction, high resolution transmission electron microscopy, visible optical absorption, Rutherford backscattering spectrometry, and residual stress measurements by Stoney's equation. In this paper we report on the Ar/N2 ratio needed to produce preferential (002) AlN growth. Correlations between X-ray diffraction and FTIR are made for highly oriented (002) AlN films. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Physics is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Physics is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Recently, ZnO attracts a wide interest as a promising material for the application in optoelectronic devices working in the blue and ultraviolet region and (when doped with magnetic impurities) in spintronic devices. Unfortunately, the technology of good, large (e.g.: 2.5–5 cm in diameter) single crystals is very difficult, even as compared with other II–VI compounds. We report on the successful growth of the ZnO crystals with a chemical vapour transport (CVT) method and on the characterisation of them. The source material is synthesised at 650 °C from oxygen and zinc vapours and subsequently, baked (as a powder) to achieve stoichiometry. The crystals grow (with the rate 1–2 mm per day) in the graphite-covered quartz ampoules containing pure (6N) hydrogen or nitrogen and a small amount of water vapour. The crystals, both as-grown and annealed in pure oxygen, are characterised by the measurements of photoluminescence spectra, transmission spectra, far infrared transmission, X-ray diffraction and electrical transport. The surface region is analysed by the secondary ion mass spectroscopy (SIMS). [Copyright &y& Elsevier]

Ternary zincblende-derived I–III–VI2 chalcogenide and II–IV–V2 pnictide semiconductors have been widely studied and some have been put to practical use. In contrast to the extensive research on these semiconductors, previous studies into ternary I–III–O2 oxide semiconductors with a wurtzite-derived β-NaFeO2 structure are limited. Wurtzite-derived β-LiGaO2 and β-AgGaO2 form alloys with ZnO and the band gap of ZnO can be controlled to include the visible and ultraviolet regions. β-CuGaO2, which has a direct band gap of 1.47 eV, has been proposed for use as a light absorber in thin film solar cells. These ternary oxides may thus allow new applications for oxide semiconductors. However, information about wurtzite-derived ternary I–III–O2 semiconductors is still limited. In this paper we review previous studies on β-LiGaO2, β-AgGaO2 and β-CuGaO2 to determine guiding principles for the development of wurtzite-derived I–III–O2 semiconductors. [ABSTRACT FROM AUTHOR]