Indium and Tin Oxide Multilayered Thin Films as Gas Sensors Based on Reactive Pulsed Laser Deposition

Pulsed laser ablation is a very interesting method to deposit thin films of several materials and compounds as oxides, nitrides, insulators, semi- and super-conductors. Indium and In Oxide polycrystalline thin films have been gown on silicon substrates by reactive pulsed laser deposition from two metallic targets of indium and Tin by a multilayered deposition, both in presence of oxygen, using a frequency doubled Nd:YAG laser. These In2O3, SnO2 thin films find valid application as antistatic coatings, transparent resistive heaters, electrical electrodes for flat panel display and electrochromic device.s A comparison has been performed, among Indium Oxide, Tin Oxide, and multilayers of Indium and Tin Oxides, to evaluate their use as gas sensor devices. The influence of the physical parameters such as the substrate temperature, the laser energy, and the oxygen pressure in the deposition chamber has been investigated. The plume has been monitored by fast photography. The characterization of the films has been performed by X-Ray Diffraction, showing a preferential orientation. A four-contact probe shows that our films exhibit an increase in resistivity when exposed to NO.