Thin Film Technology

Tin disulphide thin film on glass substrate is prepared using spray pyrolysis technique at a substrate temperature of 453 K. Using the hot probe technique the type of conductivity is found to be n type. X ray diffraction analysis revealed the polycrystalline nature of the SnS2 thin film with nano sized crystallites of dimension 5.57 nm having hexagonal structure and a preferential orientation along the (002) plane. The surface morphology has been observed using scanning electron microscope. The thickness of the film is determined as 780 nm. The absorption coefficient ? is found to vary between 1.63 x 104 cm-1 and 0.30 x 104 cm-1 correspondingly by recording the absorption data in the wavelength range 400 – 800 nm. Band gap value of 2.78 eV of direct allowed nature is observed for this pyrolysised SnS2 thin film. The room temperature resistivity of SnS2 thin film is found to be 7.18 x 104 ? cm in dark and 3.03 x 103 ? cm in light respectively. Activation energy of 0.47 eV is determined using Arrhenius plot.

Multi layer Zinc Oxide thin films with different post heating temperatures were prepared by sol-gel spin coating technique. Zinc acetate solution of 0.5M dissolved in isoproponal stabilized by Monoethanolamine was spin coated on glass substrates at 2000 rpm for 30s.After each deposition the films were pre-heated at 200°C for 10 minutes and post heated at 250,350 and 450oC in air atmosphere for 60 minutes. The structural properties were investigated by using X-ray diffraction technique and grain size was calculated. Elemental analysis and surface morphology were studied using EDX spectrum and SEM micrograph. Absorbance spectra were measured by using UV-Vis spectrophotometer and the optical band gap was calculated. The influence of post-heating temperatures on the structural and optical properties of zinc oxide thin films were reported.

Thin films of tin disulphide on glass substrates were prepared by spray pyrolysis technique using precursor solutions of SnCl2.2H2O (0.04 M) and n-n dimethyl thiourea (0.02 M - 0.12 M) at different precursor concentration ratios varied in the range 1:0.5 – 1:3, keeping other deposition parameters are constant. The films are found to be n type electrical conduction using hot probe technique. X ray diffraction analysis revealed the polycrystalline nature of tin disulphide thin film with hexagonal structure and a preferential orientation along (002) plane. The size of the tin disulphide crystallites was determined using the Full Width at Half Maximum values of Bragg peaks. The surface morphology had been observed on the surface of these films using scanning electron microscope. The optical absorption and transmittance have been recorded for the films in the wavelength range 400 - 800 nm. From the analysis of the absorption region data both allowed and forbidden optical transition nature was determined for the films in the above wavelength range. The electrical resistivity values in dark and light were determined with respect to the precursor concentration ratio.

Cadmium and Nitrogen co-doped in Tin Oxide thin films CdxN0.1-x : SnO2 with different doped molar ratio (x = 0.01,0.03 and 0.05) have been fabricated by employing Ultrasonic Spray Pyrolysis (USP) technique at the grown thicknesses ( 106.74, 67.46 and 71.82) nm, respectively. The structural, optical, morphological, and electrical properties of the fabricated films have been investigated . X-ray diffraction studies revealed a polycrystalline phase, predominantly, of CdxN0.1-x : SnO2 with (110) and (200) oriented films. The Hall effect measurement system depicted concentration a majority charges carriers (holes density ) and conductivity of the samples. The surface morphology have been observed of these films using Atomic Force Microscope (AFM). This paper deals with structural , optical and electrical properties of the films grown at the temperature substrate 300C.

Preparation of ZnO nanorod based natural dye-sensitized solar cell is reported. Seed layers were deposited on glass / ITO substrates using dip coating method with zinc acetate dihydrate as starting material. ZnO nanorods were fabricated on induced seeds by hydrothermal method using hexamethylenetetramine as a precipitant and zinc nitrate as source at 90°C. The crystal structure, orientation and surface morphology were investigated by X-Ray diffractometer and Scanning Electron Microscopy. Optical properties were studied using UV-visible spectroscopy. Prepared ZnO nanorods were employed as wide band gap semiconductor to construct natural dye-sensitized solar cells. Various natural dyes, extracted from natural plants such as leaves and flowers were used as sensitizers for natural dye-sensitized solar cells. The fill factor and solar-light-to-electricity conversion efficiency were obtained.

CdO/ZnO was fabricated by the sol-gel method. The effects of annealing process on the microstructure, transparent properties, and morphology of ZnO films were studied. The film was heated at 400?C for 5hours and the obtained samples were crushed to prepare a fine powder and taken into annealing process the temperature is constant at 700?C. The process will be preceded with different ratio. XRD results show that the different peak values in various chemical composition. In SEM image shows the nano cluster nano particles. In EDAX represents the nano composite which is to identify the compositions. UV- Absorption spectroscopy it is observed that there is a slight shift in absorption edge at 410nm towards longer wavelength side.

This study involves the preparation and characterization of hydrothermally grown zinc oxide (ZnO) nanorods. Zinc acetate dihydrate, ethanol and de-ionized water were used to prepare seed layer. Zinc nitrate and hexamethylenetetramine solution were used for growth of ZnO nanorods. The ZnO nanorods were grown for 5 hours at three different temperatures of 80°C, 90°C and 100°C and annealed at 500°C in air atmosphere. Nanorod growth temperatures are varied and the corresponding changes in structural, morphological, optical and photoluminescence properties were reported. The ZnO nanorods were investigated by XRD, SEM, UV and PL studies.

Undoped and Mn doped lead sulfide (PbS) thin films were grown on glass substrate by Successive Ionic Layer Adsorption and Reaction deposition method. Mn content in aqueous solution was varied by adding 0.1, 0.25 and 0.5 mol of manganese chloride. The structural, surface morphological, optical properties and magnetic properties of the films were studied by X-ray diffraction, scanning electron microscopy, UV-Vis spectroscopy, Atomic force microscopy and Vibrating Sample Magnetometer respectively. The X – Ray diffraction studies reveal that the Mn doped PbS thin films were polycrystalline in nature with preferential orientation along (2 0 0) plane. The scanning electron microscopy results indicate that the films were uniform. The bandgap energy of PbS and Mn doped PbS thin films are 2.4 eV and 3.1 eV. The Atomic Force Microscope results indicate that the films are uniform and adherent to the substrate. The VSM studies reveal that the thin film exhibit multi domain behavior.

Wet Chemical Synthesis method was used to synthesis Ni doped ZnS and undoped ZnS. The as-prepared products were characterized using XRD, FE-SEM, UV-VIS and PL analysis. The crystal structures, morphologies and optical properties of as-prepared samples along with the particle size, micro strain and dislocation density have been investigated. The results exhibit a crystalline hexagonal structure in particles, rod shape size about 2nm and optical bandgap of 5.56 ev.

In this study, a surface structure of zinc oxide (ZnO) nano rods prepared by hydrothermal method was investigated. The crystal structure of ZnO nano rods arrays were investigated by X-ray diffractometer (XRD) with Cu K? radiation. The surface morphologies were observed using Scanning Electron Microscope (SEM). The prepared ZnO nano rods have wide range of applications in Photo catalytic degradation of textile colouring dyes.