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Chromium-doped zinc oxide thin films (Cr: ZnO) with different Cr concentration were prepared using a homemade nebuliser spray pyrolysis system, and the influence of Cr doping level on the physical properties and the influence of light on the gas-sensing properties of ZnO films were investigated. The XRD results reveal that the hexagonal wurtzite structure of ZnO was not affected by the Cr doping. All the films have average transmittance about 85% in the visible region. The film shows good sensing behaviour against ammonia gas under dark condition than ambient (64 lx) and 150 W (5840 lx) incandescent lights. Of the tested samples, ZnO:Cr film with 2 at.-% of Cr doping shows the best response and recovery time for ammonia gas. The reasons for the enhanced sensing ability of the doped films were explained with the help of FESEM, AFM and optical results.

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A triple layer system (TaZO/Ag/TaZO) consists of tantalum doped zinc oxide (TaZO) as the top and bottom layers and metallic silver (Ag) as the intermediate layer was deposited onto glass substrates. The top and bottom layers were deposited using an inexpensive homemade Automated Jet Nebulizer Spray Technique (AJNSP) and the intermediate Ag layer was deposited using thermal evaporation technique. Three different sets of samples with top and bottom layers having thickness values around 50, 75 and 100 nm were prepared keeping the thickness of the middle layer constant (15 nm). The influence of thickness on structural,electrical, optical and photoluminescence properties along with surface morphology of the deposited triple layer system was studied. Structural study revealed that the deposited films have hexagonal wurzite structure of ZnO and x-ray photoelectron spectroscopic study confirms the presence of the expected elements in the system. Optical studies show that the overall thickness of the films influences only marginally the transmittance of the films. The decrease in sheet resistance with the increase in thickness is explained on the basis of grain boundary scattering mechanism. Among all the films examined, the multi-layer film with 75+15+75 nm thickness exhibits best quality factor (8.98 × 10 -3 (Ω/sq.) -1 ), which may be considered as a potential candidate for transparent electrode applications. To the best of our knowledge, this is the first report in which a low cost chemical technique is employed to fabricate a triple layered system. ________________________________________________________________________________________________________________

Vanadium doped zinc oxide was deposited using a homemade electrospray technique. The structural, optical, magnetic, surface morphology and electrical studies were carried out using XRD, UV-vis-NIR spectroscopy, HRSEM, AFM, photoluminescence, VSM and Hall effect, respectively. The XRD results revealed that the addition of vanadium(V) does not affect hexagonal wurtzite structure in the films. Photoluminescence study implies the increase of oxygen vacancy on surface of the samples and the hexagonal plates like grains are found on the film surface and formation of cluster as doping percentage increases. Hall effect shows the remarkable improvement in carrier concentration, resistivity and mobility. The sheet resistance decreases to 59.5 × 102 Ω/2 for 4 at% of vanadium. All the samples achieved the transmittance above 80% in the visible region and optical band gap increases. The magnetic study shows that the enhancement of paramagnetic property and the study on the performances of the samples over the light intensity shows, the enhancement in the rate of decreases in resistance, which is higher than the undoped sample ware discussed.