Decay of photo-excited conductivity of Er-doped SnO2 thin films

• Published in: Journal of materials science 2007-04, Vol.42 (7), p.2216-2221
• Main Authors: MORAIS, Evandro A, SCALVI, Luis V. A
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Crystallites; Decay; Dip coatings; Electrical properties of specific thin films; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Grain boundaries; Immersion coating; Materials science; Neodymium lasers; Other inorganic semiconductors; Physics; Semiconductor lasers; Sol-gel processes; Temperature dependence; Thin films; Tin dioxide; X-ray diffraction; YAG lasers
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-006-1320-0

Er-doped SnO2 thin films, obtained by sol-gel-dip-coating technique, were submitted to excitation with the 4th harmonic of a Nd:YAG laser (266 nm), at low temperature, and a conductivity decay is observed when the illumination is removed. This decay is modeled by considering a thermally activated cross section of an Er-related trapping center. Besides, grain boundary scattering is considered as dominant for electronic mobility. X-ray diffraction data show a characteristic profile of nanoscopic crystallite material (grain average size ≈5 nm) in agreement with this model. Temperature dependent and concentration dependent decays are measured and the capture barrier is evaluated from the model, yielding 100 meV for SnO2:0.1% Er and 148 meV for SnO2:4% Er.