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Senthamilselvi V.,Kunthavai Naachiyaar Government College for Women Autonomous | Senthamilselvi V.,P.A. College | Saravanakumar K.,P.A. College | Anandhi R.,P.A. College | And 2 more authors.
Optoelectronics and Advanced Materials, Rapid Communications | Year: 2011

Good quality CdS films were deposited on glass substrates by the simple and inexpensive SILAR (Successive Ionic Layer Adsorption and Reaction) technique from aqueous solutions having different S:Cd ratios (1:1, 3:1, 5:1 and 7:1). The annealing induced changes in the structural, surface morphological, elemental and optical properties were studied and reported. The X-ray diffraction studies revealed that a phase transformation from cubic or mixed phase to the pure hexagonal phase was caused by the annealing process at 350°C and the degree of crystallinity was enhanced very much due to annealing. The recrystallization induced by the annealing process improved the S/Cd ratio in the films and thereby made the films to acquire good stoichiometry suitable for photovoltaic applications. The annealed films found to have better transmittance (>85 %) in the visible region and enhanced optical band gap (2.50 eV). Source


Ravichandran K.,P.A. College | Senthamilselvi V.,P.A. College | Senthamilselvi V.,Kunthavai Naachiyaar Government College for Women Autonomous
Applied Surface Science | Year: 2013

The influence of indium (In) doping levels (0, 2, ..., 8 at.%) on certain physical properties of cadmium sulphide (CdS) thin films deposited using an improved successive ionic layer adsorption and reaction (ISILAR) method has been studied. In this improved SILAR technique, a fresh anionic solution was introduced after a particular number of dipping cycles in order to achieve good stoichiometry. All the deposited films exhibited cubic phase with (1 1 1) plane as preferential orientation. The calculated crystallite size values are found to be decreased from 54.80 nm to 23.65 nm with the increase in In doping level. The optical study confirmed the good transparency (80%) of the film. A most compact and pinhole free smooth surface was observed for the CdS films with 8 at.% of In doping level. The perceived photoluminescence (PL) bands endorsed the lesser defect crystalline nature of the obtained CdS:In films. The chemical composition analysis (EDAX) showed the near stoichiometric nature of this ISILAR deposited CdS:In films. © 2013 Elsevier B.V. Source


Ravichandran K.,P.A. College | Karthika K.,P.A. College | Sakthivel B.,P.A. College | Jabena Begum N.,P.A. College | And 3 more authors.
Journal of Magnetism and Magnetic Materials | Year: 2014

Manganese (Mn) doped ZnO nanopowders (0, 2, 4, 6, 8 and 10 at%) were synthesized using a simple soft chemical route and their structural, optical, surface morphological, magnetic and antibacterial properties were investigated. Structural studies show that the nanopowders exhibit hexagonal wurtzite structure of ZnO. No other secondary phases like MnO2, MnO, Mn 3O4 and Mn2O3 are observed. The blue shift observed in the photoluminescence spectra beyond the Mn doping level of 6 at% shows that there is an increase in the carrier concentration, caused by the interstitial incorporation of Zn and Mn in the ZnO matrix. From the antibacterial studies, it is found that ZnO:Mn nanopowders with higher Mn doping level (8 and 10 at%) exhibit good antibacterial efficiency against Escherichia coli (E. coli) bacteria. The magnetization curves obtained using vibrating sample magnetometer (VSM) show a sign of strong room temperature ferromagnetic behavior when the Mn doping level is 6 at% and a weak room temperature ferromagnetic behavior, when the Mn doping level is below 6 at%. Beyond 6 at% they are found to exhibit antiferromagnetic and paramagnetic properties, when the Mn doping levels are 8 and 10 at%, respectively. The SEM images indicate that there is a gradual decrease in the grain size with increase in the Mn doping level. The EDAX profile clearly confirms the presence of expected elements in the final product, in appropriate proportions. © 2014 Elsevier B.V. All rights reserved. Source


Senthamilselvi V.,AVVM Sri Pushpam College Autonomous | Senthamilselvi V.,Kunthavai Naachiyaar Government College for Women Autonomous | Ravichandran K.,AVVM Sri Pushpam College Autonomous | Saravanakumar K.,AVVM Sri Pushpam College Autonomous
Journal of Physics and Chemistry of Solids | Year: 2013

Good stoichiometric CdS films are fabricated using the successive ionic layer adsorption and reaction (SILAR) technique. Several sets of films are prepared by keeping the number of cycles of immersion as 25, 50, 75 and 100 and the effects of number of immersion cycles on the stoichiometry together with their optical and structural properties are studied. The X-ray diffraction studies showed that the films prepared from 100 cycles exhibited good crystallinity. The optical investigations revealed that the transmittance in the visible range is found to be gradually decreased as the number of immersion cycles is increased. The energy dispersive X-ray analysis showed that the stoichiometry of the SILAR deposited CdS films strongly depends on the number of immersion cycles. © 2012 Elsevier Ltd. All rights reserved. Source


Senthamilselvi V.,Kunthavai Naachiyaar Government College for Women Autonomous | Senthamilselvi V.,AVVM Sri Pushpam College Autonomous | Saravanakumar K.,AVVM Sri Pushpam College Autonomous | Anandhi R.,AVVM Sri Pushpam College Autonomous | And 3 more authors.
Journal of Materials Science: Materials in Electronics | Year: 2012

CdS films were fabricated using Successive Ionic Layer Adsorption and Reaction (SILAR) technique from starting solutions having S:Cd ratio 1:1, 3:1, 5:1 and 7:1 and their structural, surface morphological and optical properties were investigated and compared with that of their chemical bath deposited counterparts. The X-ray diffraction profiles showed that the films have cubic crystal structure with preferential orientation along the (111) plane and the intensity of the (111) plane increases for both the techniques as the S:Cd ratio increases. The energy dispersive X-ray analysis revealed that for SILAR deposited films, the S/Cd ratio in the sample increases from 0.8308 (for S:Cd 1:1) to 1.04 (for S:Cd 7:1) as the molar concentration of sulphur in the starting solution increases. But for CBD films, the S/Cd is only ∼0.80 for all concentrations of sulphur in the starting solution. The optical band gap increases with the increase in S:Cd ratio in the starting solution in both the techniques. © 2011 Springer Science+Business Media, LLC. Source

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