Implantation-assisted Co-doped CdS thin films: Structural, optical, and vibrational properties
TL;DR: In this paper, structural, optical, vibrational, and morphological properties of cobalt-doped CdS thin films, prepared by 90 keV Co+ implantation at room temperature, were reported.
Abstract: This paper reports on structural, optical, vibrational, and morphological properties of cobalt-doped CdS thin films, prepared by 90 keV Co+ implantation at room temperature. In this work, we have used cobalt concentration in the range of 0.34–10.8 at. %. Cobalt doping does not lead to the formation of any secondary phase, either in the form of metallic clusters or impurity complexes. However, with increasing cobalt concentration a decrease in the optical band gap, from 2.39 to 2.26 eV, is observed. This reduction is addressed on the basis of band tailing due to the creation of localized energy states in association with Urbach energy calculations. In addition, implantation gives rise to grain growth and increase in the surface roughness. Size and shape fluctuations of individual CdS grains, at higher fluences, give rise to inhomogeneity in strain. The results are discussed in the light of ion-matter interaction in the keV regime.
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TL;DR: In this paper, Nanoporous thin films of Cd1−xCuxS (0≤x≤0.06) were grown on a heated glass substrate employing a home-made spray pyrolysis technique.
72 citations
TL;DR: In this paper, pure and cobalt doped CdS nanoparticles were successfully synthesized by surfactant assisted simple chemical co-precipitation method and size of the particles around 3nm and cubic zincblende structure were revealed by the X-ray diffraction pattern.
66 citations
TL;DR: In this paper, the synthesis of Co-doped CdS nanoclusters (Cd1−xCoxS) for different doping concentrations (x = 0.10, 0.20 and 0.30) and characterization of their structural, optical, and magnetic properties were reported.
54 citations
TL;DR: In this paper, X-ray diffraction results showed that all the samples had hexagonal wurtzite structure with the (1 − 0 − 1) preferred orientation, which was found from scanning electron microscopy that an increase in the grain size was observed after F-doping.
53 citations
TL;DR: Experimental evidence points to charge transfer at the CdS-RGO interface playing a dominant role in the photocatalytic hydrogen production activity and theoretical analysis finds that the interfacial charge transfer is a balance between the effective single-electron- and hole-transfer probability and the surface free electron and hole concentration.
Abstract: Dual-band-gap systems are promising for solar water splitting due to their excellent light-harvesting capability and high charge-separation efficiency. However, a fundamental understanding of interfacial charge-transfer behavior in the dual-band-gap configuration is still incomplete. Taking CdS/reduced graphene oxide (CdS/RGO) nanoheterojunctions as a model solar water splitting system, we attempt here to highlight the interaction-dependent interfacial charge-transfer behavior based on both experimental observations and theoretical calculations. Experimental evidence points to charge transfer at the CdS-RGO interface playing a dominant role in the photocatalytic hydrogen production activity. By tuning the degree of reduction of RGO, the interfacial interaction, and, thereby, the charge transfer can be controlled at the CdS-RGO interface. This observation is supported by theoretical analysis, where we find that the interfacial charge transfer is a balance between the effective single-electron- and hole-transfer probability and the surface free electron and hole concentration, both of which are related to the surface potential and tailored by interfacial interaction. This mechanism is applicable to all systems for solar water splitting, providing a useful guidance for the design and study of heterointerfaces for high-efficiency energy conversion.
42 citations
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TL;DR: A review of existing widely-cited tables of ion stopping and ranges can be found in this paper, where a brief exposition of what can be determined by modern calculations is given.
Abstract: The stopping and range of ions in matter is physically very complex, and there are few simple approximations which are accurate. However, if modern calculations are performed, the ion distributions can be calculated with good accuracy, typically better than 10%. This review will be in several sections:
a)
A brief exposition of what can be determined by modern calculations.
b)
A review of existing widely-cited tables of ion stopping and ranges.
c)
A review of the calculation of accurate ion stopping powers.
10,060 citations
TL;DR: In this article, the effects of the competition between the long-range electrostatic forces and the short-range forces due to anisotropy in the interatomic force constants on the vibrational spectrum has been included.
Abstract: First-order Raman scattering from BeO, ZnO, ZnS, and CdS, all having the wurtzite structure (${C}_{6v}$), has been investigated. A discussion of the effects of the competition between the long-range electrostatic forces and the short-range forces due to anisotropy in the interatomic force constants on the vibrational spectrum has been included. A series of scattering diagrams are presented showing the geometrical arrangements necessary to observe all the $k=0$ phonons for this type of crystal structure. In BeO the ${E}_{2}$ mode was resolved from the transverse modes for the first time. The assignments of the ${E}_{2}$ modes in ZnS differ from previous investigations. From absolute intensity measurements, electro-optic coefficients for BeO, ZnO, and CdS were determined.
886 citations
TL;DR: Theoretical size and strain profile functions are given by the minimum number of parameters required by physics and are compared with TEM results as mentioned in this paper, which provides crystallite size, size distribution and dislocation structure.
752 citations
TL;DR: It is shown by molecular dynamics that cascades in metals may lead to the formation of both vacancy and interstitial dislocation loops, and a new mechanism of defect production based on interstitial prismatic dislocation-loop formation is proposed.
Abstract: We present molecular-dynamics computer-simulation studies of 25-keV displacement cascades in Cu at low temperature. We observe the splitting of a cascade into subcascades and for the first time show by molecular dynamics that cascades in metals may lead to the formation of both vacancy and interstitial dislocation loops. We propose a new mechanism of defect production based on interstitial prismatic dislocation-loop formation and discuss its consequences regarding the primary state of damage in irradiated metals.
196 citations
TL;DR: In this paper, the lattice contraction indicates the occurrence of surface optimization/reconstruction during the growth, which results in the high quantum yield of the obtained CdSe NCs.
Abstract: Colloidal CdSe nanocrystals (NCs) with high photoluminescent quantum yield are fabricated by a method adopting a large initial Se:Cd ratio of the precursors in the solution. X-ray diffraction and Raman measurements confirm that there exists lattice contraction in the free-standing wurtzite CdSe NCs. The lattice contraction indicates the occurrence of surface optimization/reconstruction during the growth, which results in the high quantum yield of the obtained CdSe NCs.
130 citations