V. Dhanasekaran

Spectral properties of aluminium doped zinc oxide thin films prepared by SILAR method

The spectral properties of undoped and Al doped ZnO nano thin films prepared using double dip method otherwise called SILAR method (Successive Immersion Layer Adsorption Reaction) are reported. The thin films were having polycrystalline hexagonal structure. The optical properties of these films are studied and reported. The optical constants like the band gap (Eg), refractive indices (n, k), dielectric constant (ε), optical conductivity (σ), were estimated using an approximation algorithm developed from established procedures using transmittance spectrum of the thin films. The average excitation energy (E0), oscillator strength (Ed), effective mass (m*), plasma frequency (ωp), static dielectric constant (ε∞) and carrier concentration (N) are also estimated and reported. The highly transparent thin films showed nanowires protruding from stacked nanorods on SEM inspection that signifies the suitability of these thin films for gas sensors.

SEM and AFM studies of dip‐coated CuO nanofilms

Cupric oxide (CuO) semiconducting thin films were prepared at various copper sulfate concentrations by dip coating. The copper sulfate concentration was varied to yield films of thicknesses in the range of 445–685 nm by surface profilometer. X‐ray diffraction patterns revealed that the deposited films were polycrystalline in nature with monoclinic structure of (−111) plane. The surface morphology and topography of monoclinic‐phase CuO thin films were examined using scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. Surface roughness profile was plotted using WSxM software and the estimated surface roughness was about ∼19.4 nm at 30 mM molar concentration. The nanosheets shaped grains were observed by SEM and AFM studies. The stoichiometric compound formation was observed at 30 mM copper sulfate concentration prepared film by EDX. The indirect band gap energy of CuO films was increased from 1.08 to 1.20 eV with the increase of copper sulfate concentrations. Microsc. Res. Tech., 2013.

Optical and magnetic properties of Mn doped ZnO thin films grown by SILAR method

Polycrystalline Mn doped ZnO (MZO) semiconductor thin films were deposited onto glass substrates employing different number of dipping at room temperature using Successive Ionic Layers by Adsorption Reaction (SILAR) technique. The thin film deposition conditions were optimized by altering the various deposition parameters based on their structure. The structural study was carried out using X-ray diffractometer (XRD). The XRD analysis indicated that there is no change in the structure of ZnO thin films due to Mn doping. The films exhibited hexagonal wurtzite structure. The structural studies on Mn doped samples revealed that the predominant orientation is (002) lattice plane and the position of this orientation shifted toward lower angle during doping. The intensity of photoluminescence (PL) emission of ZnO is found to be augmented for Mn doped samples. The room temperature Raman spectra measurements revealed the presence of additional modes. The Vibrating Sample Magnetometer (VSM) studies show that MZO thin film has ferromagnetic properties.

Morphological properties of Ag2SeTe nano thin films prepared by thermal evaporation

Semiconducting silver selenide telluride (Ag2SeTe) thin films were prepared with different thicknesses onto glass substrates at room temperature using thermal evaporation technique. The structural properties were determined as a function of thickness by X‐ray diffraction exhibiting no preferential orientation along any plane; however, the films are found to have peaks corresponding to mixed phase. The morphology of these films was studied using scanning electron microscope and atomic force microscopy respectively, and is reported. The morphological properties are found to be very sensitive to the thin film thickness. The composition of the films is also estimated using energy dispersive analysis using X‐rays and are also reported.

Morphology selection for cupric oxide thin films by electrodeposition

Polycrystalline cupric oxide thin films were deposited using alkaline solution bath employing cathodic electrodeposition method. The thin films were electrodeposited at various solution pH. The surface morphology and elemental analyzes of the films were studied using scanning electron microscopy (SEM) and energy dispersive X‐ray analysis, respectively. SEM studies revealed that the surface morphology could be tailored suitably by adjusting the pH value during deposition. Mesh average on multiple lattice mode atomic force microscopy image was obtained and reported. Microsc. Res. Tech. 2011.

Annealing effect of double dip coated ZnAl2O4 thin films

Thin films of ZnAl2O4 were prepared by dip technique involving chemical solutions. Investigations on the effect of post heat treatment on the structural, optical properties of ZnAl2O4 thin films were studied and reported. Xray diffraction patterns revealed that the thin films are polycrystalline cubic structure of ZnAl2O4. The microstructural properties of ZnAl2O4 thin films were calculated and crystallite size tends to increase with increase of annealing temperatures. The texture coefficients have been evaluated and found to be greater than unity revealing high texturing of the architecture of the film. The optical band gap values were found to be in the range of 3.48 – 3.62 eV. The n and k were found to decrease with increase of post annealing temperature. The SEM revealed the uniform distribution of spherical grains.

Effects of bath temperature on electroplated SnSe thin films

Tin selenide (SnSe) thin films were deposited onto indium doped tin oxide coated (ITO) glass substrates by electro deposition technique. The deposition bath contains a solution mixture consisting SnCl2 and Na2SeO3. X-ray diffraction studies revealed orthorhombic structure of SnSe films and various micro structural parameters such as crystallite size, dislocation density and strain were calculated. Optical properties were determined by UV-vis-NIR double beam spectrophotometer and direct transition energy band gap was estimated as 1.1 eV. Morphological studies reveal nano rod shaped grains covering the surface of the film and the results are discussed.

Substrate effects on SILAR route synthesized CuO thin films

Cupric oxide (CuO) thin films are deposited using SILAR method onto various substrates. The X-ray diffraction patterns revealed that the deposited films are polycrystalline in nature with monoclinic structure. The microstructural parameters of chemical bath deposited CuO thin films are calculated using the structural studies. The optical band gap value is determined using transmission spectrum of CuO thin films and the results are discussed.

Effect of annealing temperature on CdO thin films

Cadmium oxide thin films were prepared by double dip technique on glass substrates. The prepared films were annealed at different temperature such as 200°C, 300°C and 400°C. The structural studies revealed that the CdO films are in polycrystalline in nature with cubic structure. The microstructrual parameters of cubic CdO thin films were calculated. The optical transmission and absorption spectrum of CdO thin films were recorded at room temperature. The direct transition band gap values are determined using Taucs plot and energy band gap increases with increase of annealing temperature.

Structural and Magnetic Properties of Electrodeposited Co‐Ni‐P Alloy Thin Films

Various cobalt sulphate concentration of Co‐Ni‐P alloy thin films deposited on the pre‐cleaned copper substrates by galvanostatic mode. The cobalt sulphate concentration influence on the structural and magnetic properties of the films was investigated using X‐ray diffraction patterns and VSM studies, respectively.