[en] ZnO films have been reproducibly grown using chemical deposition and radio-frequency sputtering techniques. These films are polycrystalline or amorphous, but are stable, uniform and lend themselves to material characterization by Auger and x-ray analysis techniques, and electrical measurements. SnO₂ films have been reproducibly grown by chemical vapor deposition, vacuum deposition and radio-frequency sputtering techniques. These films are also polycrystalline or amorphous, and lend themselves to material characterization and measurements. By vacuum deposition techniques, Si-SnO₂ heterojunctions have been grown, which exhibit good rectification properties. An original thermodynamic analysis of the growth of SnO₂ by a chemical vapor deposition technique based on the reaction between SnCl₄ and H₂O has been developed and submitted for publication. Pd-SiO₂-Si Schottky barrier diodes exhibiting excellent rectification properties have been successfully fabricated. A formalism has been established for the analysis of the behavior of these devices in the presence of H₂, H₂S and CO. The ZnO films grown by chemical deposition have proven to be sensitive to CO and CH₄. Sputtered ZnO films are sensitive to O₂ and H₂. SnO₂ films grown by chemical vapor deposition are not very sensitive to gases. Sputtered films, however, are very sensitive to H₂ and H₂S. The Pd-SiO₂-Si diodes are extremely sensitive to H₂, H₂S and NH₃, and, under certain conditions, to CO. A microprocessor data processing system has been developed incorporating gas sensors in the presence of a variety of gases and gas mixtures