2016 International Conference on Sustainable Energy, Environment and Information Engineering (SEEIE 2016) ISBN: 978-1-60595-337-3 Effect of Firing Temperature on Electrical and Structural Characteristics of Screen Printed In 2 O 3 Thick Films SUSHMA KULKARNI 1,* and DNYANESHWAR PATIL 2 1 S.P.H. Mahila Mahavidyalaya Malegaon-camp(Nashik) 423105 M.S. India 2 Department of Electronics, North Maharashtra University Jalgaon, 425001M.S., India Keywords: In 2 O 3 , Thick films, Activation energy, Resistivity. Abstract. In 2 O 3 thick films were prepared on porous alumina (Al 2 O 3 ) substrate by using standard screen printing technique and fired at different temperatures from 750 º C to 950 º C in air atmosphere. The DC resistance of film was measured by half bridge method in air atmosphere at different temperatures. The films were showing decrease in resistance with increase in temperature indicating semiconductor behavior. The resistivity (ρ), activation energy (∆E) and temperature coefficient of resistance (TCR) are evaluated at different firing temperatures. Samples were characterized by X- ray diffraction (XRD) technique, scanning electron Microscopy (SEM)), Energy Dispersive Spectroscopy (EDX) and Atomic force microscopy (AFM) technique, for compositional, phase confirmation and surface growth and morphology study. Introduction Indium oxide (In 2 O 3 ) belongs to class of wide band gap metal oxides (Eg = 3.6 eV) and is of interest for many device applications and fundamental research [1]. It has interesting properties such as high transparency to visible light, high electrical conductance. In 2 O 3 has been widely used in microelectronic field as gas detectors, window heaters, solar cells, memory devices, and flat panel materials. In the last years the gas sensing and properties of In 2 O 3 as semiconductor gas sensor have been investigated [2]. Several deposition methods have been used to grow In 2 O 3 films such as spray pyrolysis, evaporation, chemical vapour deposition, magnetron sputtering, pulsed laser deposition, a sol-gel technique and a screen printing technique [3]. The screen printing technique was introduced in the later part of the 1950’s to produce compact, robust and relatively inexpensive hybrid circuits for many purposes. Later on a thick film technique has attracted attention for the sensor field. Screen printing is a viable and economical method to produce thick films of various materials [4]. In this paper, preparation of In 2 O 3 thick films by standard screen printing technique and their electrical and structural properties at different firing temperatures have been investigated. Experimental Thick Films Fabrication The Commercially available yellowish In 2 O 3 powder (Loba Chem. purity 99.99%) was weighed and calcined in air at 300 º C for 2 hour. Thick films of calcined powder were fabricated using standard screen printing method. Paste for thick film printing consists of two parts (i) solid phase and (ii) liquid phase. A ratio of 70 to 30 was taken for solid and liquid phase. Solid phase is of functional material (powder and glass frit) whereas liquid phase is of organic vehicle which are temporary binders. Calcined indium oxide powder was used a functional materials along with 5% (by weight) of locally prepared glass frit based on lead borosilicate composition. Ethyl cellulose (EC, Aldrich) and Butyl Carbitol Acetate (BCA, Aldrich) were used as temporary binders. These binders are known to give thixotropic property to the paste. The paste for the thick film printing was prepared by finely grinding the calcined powder in agate-mortar and pestle. Then EC was added and well mixed with powder. Then BCA was added drop by drop and mixed well until the required viscosity was achieved, suitable for screen printing. Viscosity of the paste was controlled in a way 403