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Usharani K.,AVVM Sri Pushpam College | Balu A.R.,AVVM Sri Pushpam College | Balu A.R.,New Housing Unit
Acta Metallurgica Sinica (English Letters) | Year: 2015

Thin films of zinc-doped cadmium oxide with different Zn-doping levels (0, 2, 4, 6, and 8 at%) were deposited on glass substrates by employing an inexpensive, simplified spray technique using perfume atomizer at relatively low substrate temperature (375 °C) compared with the conventional spray method. The effect of Zn doping on the structural, morphological, optical, and electrical properties of the films was investigated. XRD patterns revealed that all the films are polycrystalline in nature having cubic crystal structure with a preferential orientation along the (1 1 1) plane irrespective of Zn-doping level. Zn-doping level causes a slight shift in the (1 1 1) diffraction peak toward higher angle. The crystallite size of the films was found to be in the range of 28-37 nm. The band gap value increases with Zn doping and reaches a maximum of 2.65 eV for the film coated with 6 at% Zn doping and for further higher doping concentration it decreases. Electrical studies indicate that Zn doping causes a reduction in the resistivity of the films and a minimum resistivity of 15.69 X cm is observed for the film coated with 6 at% Zn. © 2014 The Chinese Society for Metals and Springer-Verlag Berlin Heidelberg. Source


Sivaraman T.,A Veeriya Vandayar Memorial Sri Pushpam College | Nagarethinam V.S.,A Veeriya Vandayar Memorial Sri Pushpam College | Balu A.R.,A Veeriya Vandayar Memorial Sri Pushpam College | Balu A.R.,New Housing Unit | Usharani K.,A Veeriya Vandayar Memorial Sri Pushpam College
Journal of Materials Science: Materials in Electronics | Year: 2016

CdS thin films simultaneously doped with Mg and Cl at different doping concentrations (0, 2, 4, 6 and 8 at%) were prepared on glass substrates by spray pyrolysis technique using perfume atomizer at 400 °C. The effect of Mg and Cl doping concentration on the structural, morphological, optical and electrical properties of the deposited films were investigated using X-ray diffraction (XRD), scanning electron microscopy, UV–Vis spectroscopy and dc electrical measurements, respectively. XRD analysis showed that the undoped and doped CdS films exhibit hexagonal structure with a preferential orientation along the (0 0 2) plane. The 2θ angle position of the (0 0 2) peak of the doped films was shifted towards a higher angle with increasing Mg and Cl concentration. The UV–Vis–NIR absorption spectra of Mg and Cl doped thin films are measured and classical Tauc approach was employed to estimate their band gap energies. The increase in band gap energy from 2.46 to 2.73 eV with the reduction in crystallite size supports quantum size effect. Raman spectra implied that more defects existed in the doped samples. Electrical studies showed that all the films have resistivity in the order of 101 Ω-cm and the CdS film with 6 at% Mg and Cl concentration has a minimum resistivity of 1.332 × 101 Ω-cm. © 2015, Springer Science+Business Media New York. Source


Rajashree C.,New Housing Unit | Balu A.R.,New Housing Unit | Nagarethinam V.S.,New Housing Unit
Journal of Materials Science: Materials in Electronics | Year: 2016

Nanostructured ternary PbMgS thin films with different Mg concentrations (0, 2, 4, 6 and 8 at.%) were prepared on glass substrates kept at 400 °C by spray pyrolysis technique. Crystalline quality, morphology, optical and electrical properties of the as deposited PbMgS thin films were characterized using X-ray diffraction, field emission scanning electron microscopy (FESEM), UV–Vis–NIR double beam spectrophotometer and two point probe setup respectively. It is observed that both the undoped and doped PbS films have face-centered cubic structure with a (2 0 0) preferential orientation. Appearance of the 2LO mode in the Raman spectra revealed good crystalline quality of the as deposited films, and the characteristic bands agrees with that of galena PbS. Decreased crystallite size observed with doping leads to an increase in the optical band gap values from 2 to 2.18 eV which may be attributed to quantum size effect. FESEM images clearly show that the as synthesized PbMgS thin film morphology modifies from nano sized needles to disc shaped structures with Mg incorporation. The addition of Mg into PbS lattice was confirmed by EDX analysis. Electrical studies show that the film resistivity decreases from 7.29 × 103 to 0.4369 × 103 Ω-cm with increase in Mg concentration. Enhancement in the film transparency, widened band gap energy and decreased resistivity observed make PbMgS thin films suitable for solar cell applications. © 2016 Springer Science+Business Media New York Source


Noorunisha T.,New Housing Unit | Nagarethinam V.S.,New Housing Unit | Suganya M.,New Housing Unit | Praba D.,Government of Tamilnadu | And 3 more authors.
Optik | Year: 2016

Nanostructured ternary CdZnO thin films with zinc concentrations (0, 2, 4, 6 and 8 wt%) were prepared by spray pyrolysis technique using perfume atomizer on glass substrates at 375 °C. The effect of doping concentration on the structural, morphological, optical and electrical properties of the films was studied and from the results obtained it is observed that the CdZnO film with 6 wt% Zn doping concentration has better physical properties and this film is subjected to post annealing in air at different temperatures. The effect of thermal annealing on the properties of the deposited films was systematically studied. The XRD patterns reveal that the films are polycrystalline in nature with cubic structure and are highly textured along (1 1 1) preferential orientation. The SEM and AFM images confirmed these results and showed more crystallization up to 300 °C annealing temperature. Film transparency decreases with annealing temperature. Analysis of the absorption edge revealed that the optical band gap energies of the films was red shifted with annealing temperature. The annealed films have a resistivity in the order of 101 Ω cm. Increased transparency and reduced resistivity observed for the CdZnO films make them suitable for optoelectronic device applications especially as window layer in solar cells. © 2015 Elsevier GmbH. All rights reserved. Source

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