Porous nano and micro crystalline tin oxide films were deposited by RF Magnetron Sputtering and doctor blade techniques, respectively. Electrical resistance and impedance spectroscopy measurements, as a function of temperature and atmosphere, were performed in order to determine the influence of the microstructure and working conditions over the electrical response of the sensors. The conductivity of all samples increases with the temperature and decreases in oxygen, as expected for an n-type semiconducting material. The impedance plots indicated the existence of two time constants related to the grains and the grain boundaries. The Nyquist diagrams at low frequencies revealed the changes that took place in the grain boundary region, with the contribution of the grains being indicated by the formation of a second semicircle at high frequencies. The better sensing performance of the doctor bladed samples can be explained by their lower initial resistance values, bigger grain sizes and higher porosity.

Thin films of bioactive glass-ceramic have been deposited on titanium substrates by the Pulsed Laser Deposition (PLD) technique under different experimental conditions. The effect of parameters such as deposition pressure and temperature of heat treatments was studied. The microstructure and the crystalline phases of the coatings were characterized using SEM, EDX and XRD analysis; the phases present were titanium oxides, calcium magnesium silicates and phosphates. The adhesion of the as-deposited films has been examined by scratch tests. The interfacial adhesion of the coatings was better when the deposition was performed at low pressure. Samples were immersed in simulated body fluid (SBF), and a calcium-phosphate precipitate was observed on the surface of less crystallized samples, suggesting that there is some relationship between surface reactivity and crystallinity.

The performance of different platinum electrodes used as resistive heating elements was studied. Pt films having different thickness were deposited by RF magnetron sputtering at room temperature followed by post-deposition annealing at 700 ºC or made in-situ at 700 ºC. The Pt films were deposited over oxidized silicon, using Ti or Zr buffer layers. The resistance dependence on temperature was studied by applying increasing currents (up to 2A) to the Pt films. Changes in the microstructure of the Pt films account for the changes in the temperature coefficient of resistance as a function of the deposition parameters. The maximum substrate temperature (675 ºC) was obtained when using 200 nm Pt films deposited at 700 ºC over Ti, with a power consumption of only 16 W.