Raman and photoacoustic spectroscopies of SnO2 thin films deposited by spin coating technique

Abstract SnO2 thin films were grown on glass substrate using a spin-coating technique. The films grown in different layers and subjected to pressure-assisted heat treatment (PAHT) were characterized by Raman spectroscopy and Photoacoustic measurements. Raman spectroscopy showed the SnO2 presence in the grown thin film and in the substrate. In addition, PAHT can change the adsorbed oxygen and the oxygen vacancies in the film. These changes strongly influence the band gap energy of samples, which were investigated by photoacoustic spectroscopy and showed a blueshift in samples after PATH treatment. A depth profile analyze with excitation on the substrate indicated a slow attenuation of the photoacoustic signal relative to tin dioxide up to 120 μm, which represents SnO2 presence up to 40 μm deep in the glass substrate. The average effective thermal diffusivity, determined by two-beam phase-lag photoacoustic method was α=(0.017 ± 0.001) cm2/s, according the literature for pure tin dioxide.