Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
3 results
Search Results
Item Properties of CdxZn1-xO thin films and their enhanced gas sensing performance(Elsevier Ltd, 2017) Bharath, S.P.; Bangera, K.V.; Shivakumar, G.K.CdxZn1-xO(0 ? x ? 0.20) thin films with different Cd concentrations were successfully deposited on glass substrate using spray pyrolysis technique. X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDAX) were used for structural, surface morphological and compositional characterization. The XRD analysis revealed that the synthesized films were hexagonal in structure with (002) orientation. The SEM studies confirm the formation of homogeneous and uniform films. Optical transmittance and electrical conductivity of the films were evaluated using UV–Visible spectroscopy and two probe method respectively. The optical studies showed that the CdxZn1-xO thin films have optical transmittance in entire visible region. The resistivity of undoped films were very high and it decreases with addition of cadmium. The gas sensing properties were investigated at optimal temperature of 350 °C for various volatile organic compounds like acetone, ethanol and methanol. The CdxZn1-xO thin films with 10 at. % cadmium concentration showed the sensitivity of 50% for 1 ppm ethanol. © 2017 Elsevier B.V.Item Enhanced gas sensing properties of indium doped ZnO thin films(Academic Press, 2018) Bharath, S.P.; Bangera, K.V.; Shivakumar, G.K.Indium doped ZnO (InxZn1-xO, 0 ? x ? 0.05) thin films were deposited on to soda lime glass substrate by employing spray pyrolysis as deposition technique. Effect of doping concentration on characteristics of thin films were examined by XRD, SEM, UV-Visible spectroscopy, electrical and gas sensing measurements. XRD analysis demonstrates polycrystalline nature of thin films and also shows the shift in orientation from (002) to (101) crystal plane with increase in indium doping concentration. Surface morphological analysis shows the formation of homogeneous particle like nanostructures. Optical transmittance determined from UV-Visible spectroscopy was in the range of 80–95%, which was decreasing with increase in indium doping concentration. Maximum electrical conductivity was achieved at an optimal indium doping concentration of 3 at.%. The gas sensing properties were examined for different concentration of volatile organic compounds like acetone, ethanol and methanol for different doping levels. In0.03Zn0.97O thin films showed good sensitivity towards ethanol, with sensitivity of 30% towards 25 ppm of ethanol. © 2018 Elsevier LtdItem Synthesis and characterization of Cu 1-x Zn x O composite thin films for sensor application(Elsevier Ltd, 2019) Bharath, S.P.; Bangera, K.V.; Shivakumar, G.K.Cu 1-x Zn x O composite thin films were prepared using industrially applicable spray pyrolysis technique for volatile organic compound (VOCs)sensor application. Sensing properties for different concentration of VOCs such as acetone, ethanol and methanol were studied at different sensor operating temperature. XRD studies on prepared thin films confirmed formation of CuO[sbnd]ZnO composite thin films with presence of different peaks for monoclinic structured CuO and hexagonal structure ZnO, it was also observed that formation of composite material improves sensing property towards VOCs. Granular morphology observed from SEM images were also contributed to enhance sensitivity of Cu 1-x Zn x O thin films. Hot probe experiment reveals that all the thin films were p-type in conductivity nature. Maximum electrical conductivity was achieved for Cu 0.75 Zn 0.25 O composite thin films, which also showed highest sensing property for VOCs. Cu 0.75 Zn 0.25 O thin films were selective towards ethanol and were capable of detecting 1 ppm of ethanol at operating temperature of 290 °C. © 2019