Tailoring of highly porous SnO2 and SnO2-Pd thin films

摘要： Tin oxide is a material that attracts attention due to varieties of technological applications. The main parameters that influence its properties are morphology, crystalline structure and stoichiometry. To influence these parameters researchers try to develop nanostructured thin films that would conform technological application. Here, we report the preparation and characterization of highly porous SnO2 and Pd doped SnO2 thin films. The films were deposited in form of nanorods with controllable geometry. Such morphology was achieved by utilizing glancing angle deposition (GLAD) with assisted magnetron sputtering. This arrangement allowed preparation of slanted pillars, zig-zag structure, vertically standing posts, spiral posts and “bush”-like structures. We calculated that slanted pillars possess highest surface area among the films listed. Then, sets of slanted pillars were deposited and studied in more details. The influence of substrate annealing during the film deposition and Pd doping on the morphology, crystalline structure and stoichiometry of the films are discussed. Characterizations of the tin oxide films were performed by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and synchrotron radiation photoelectron spectroscopy (SRPES). GLAD with assisted magnetron sputtering allowed us to deposit broad range of SnO2 nanostructures while annealing of the substrate during deposition affects the films crystallinity. Also, we find that doping of the SnO2 films with Pd leads to alloy phase formation. These findings can be applied in variety of applications including gas sensing, catalysis, optics and electronics.