EFFECT OF SURFACE MODIFICATION ON STRUCTURAL, OPTICAL AND AMMONIA SENSING PROPERTIES OF INDIUM OXIDE FILMS

Indium oxide (In2O3) films have been prepared by thermal oxidation of pre-deposited indium films onto glass substrate kept at room temperature (35°C). These films were dipped into an aqueous solution (0.1 M) of lithium chloride (LiCl) and aluminum chloride (AlCl3) followed by being fired at 500°C. Based on X-ray diffraction results, it has been observed that pure and Li modified In2O3 films are polycrystalline in nature while Al modified In2O3 film has a prominent peak corresponding to 222 plane of In2O3. Field emission scanning electron microscopy of pure film shows smaller grains which get transformed to bigger ones for Li modified In2O3 film. In case of Al modified In2O3 film agglomerated small grains are observed. This film also reveals the response of 60% for 100 ppm of ammonia vapors at room temperature. The transparency increased from 23–36% to 53–67% in visible region with Li modification of pure In2O3 film.