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A sensor for ammonia gas and ethanol vapour has been fabricated using indium oxide thin film as sensing layer and indium tin oxide thin film encapsulated in poly(methyl methacrylate) (PMMA) as a miniature heater. For the fabrication of miniature heater indium tin oxide thin film was grown on special high temperature corning glass substrate by flash evaporation method. Gold was deposited on the film using thermal evaporation technique under high vacuum. The film was then annealed at 700 K for an hour. The thermocouple attached on sensing surface measures the appropriate operating temperature. The thin film gas sensor for ammonia was operated at different concentrations in the temperature range 323-493 K. At 473 K the sensitivity of the sensor was found to be saturate. The detrimental effect of humidity on ammonia sensing is removed by intermittent periodic heating of the sensor at the two temperatures 323K and 448 K, respectively. The indium oxide ethanol vapour sensor operated at fixed concentration of 400 ppm in the temperature range 293-393 K. Above 373 K, the sensor conductance was found to be saturate. With various thicknesses from 150-300 nm of indium oxide sensor there was no variation in the sensitivity measurements of ethanol vapour. The block diagram of circuits for detecting the ammonia gas and ethanol vapour has been included in this paper.

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Thin film solar cells have been prepared and investigated by using indium-doped n-CdSe in conjunction with p-ZnTe. The films are prepared on indium tin oxide (ITO) coated glass substrates by the thermal evaporation. Thin film layers have been deposited without breaking vacuum by utilizing a mask rotating system. Silver has been used as a stimulator for bringing improvement in the crystallinity and electrical behaviour of ZnTe thin films. Indium is used for obtaining the back ohmic contacts. The solar cells thus produced have been characterized by I -V-, C -V-, and spectral response measurements. The maximum open circuit voltage, the short circuit current density, and the efficiency are obtained as 415 mV, 11.60 mA cm-* and 1.86%, respectively under 100 mW cm-* input optical power. The diffusion potential and depletion width are found to be 1.42 eV and 21 nm, respectively.