This paper compared the effects of A. indica plant proteins over chemical methods in the morphology of zinc oxide nanoparticles (ZnO NPs) prepared by a co-precipitation method, and ethanol sensing performance of prepared thin films deposited over a fluorene-doped tin oxide (FTO) bind glass substrate using spray pyrolysis technique. The average crystallite sizes and diameters of the grain-sized cluster ZnO NPs were 25 and (701.79 ± 176.21) nm for an undoped sample and 20 and (489.99 ± 112.96) nm for A. india dye-doped sample. The fourier transform infrared spectroscopy (FTIR) analysis confirmed the formation of the Zn–O bond at 450 cm⁻¹, and also showed the presence of plant proteins due to A. indica dye extracts. ZnO NPs films exhibited good response (up to 51 and 72% for without and with A. indica dye-doped extracts, respectively) toward ethanol vapors with quick response-recovery characteristics at a temperature of 250 °C for undoped and 225 °C for A. indica dye-doped ZnO thin films. The interaction of A. indica dye extracts helps to decrease the operating temperature and increased the response and recovery rates of the sensor, which may be due to an increase in the specific surface area, resulting in adsorption of more oxygen and hence high response results.

Fluorine doped Tin Oxide (FTO) thin films were deposited on glass substrates by home built spray pyrolysis setup at (400 ± 5)ºC. The method was found to be very economic and functional. The deposited FTO films were highly transparent and had low resistivity. The structural investigation of as-prepared films was performed using X-ray diffraction. Our results showed that a deposited FTO film was of polycrystalline nature with preferential orientation along (211) planes. The direct band gap value was found to be 3.25eV for 10% FTO film. The sheet resistance of this film was measured to be 68 Ω/ square. The effect of fluorine doping concentration on its band gap was also studied in this report.The Himalayan Physics Vol. 6 & 7, April 2017 (58-60)

In recent times, the importance of nanostructure of metal oxide semiconductor (MOS) as a gas sensing material is rising tremendously. Among various metal oxide semiconductors ZnO has potential to be used as a sensor for several toxic gases. In this work, we investigated the influence of Fe doping into ZnO to detect various concentrations of ethanol vapour. Pristine and Fe doped ZnO (Fe-ZnO) films were deposited on glass substrates using a spin coating technique wherein the concentration of Fe can be easily controlled. The crystallite size and surface morphology of ZnO samples were characterized by XRD, SEM and EDX techniques. The sensor performance in terms of gas response (R) of ZnO and Fe-ZnO gas sensors towards ethanol vapour were measured in the 100 to 300°C temperature range using DC electrical resistance. Fe doped ZnO samples showed enhancement in gas response due to increase in specific surface area originated from reducing grain size after doping. The 2% Fe-ZnO sample showed the good response of 40.9 for 400 ppm of ethanol vapour exposure at 260°C. This was found to be better than reported values for ZnO prepared by different methods.