Characterization of porous indium tin oxide thin films using effective medium theory

Effective medium theory was used to model optical properties in the 0.3 - 30 mum wavelength range for films comprised of nanoparticles of a transparent conducting oxide that are connected in a percolating network characterized by a filling factor f. The model is based on charge carrier density n(e) and resistivity rho of the particles, and it enables analyses of these microscopic parameters upon posttreatment of the film. The theory was used to interpret data on spin coated layers consisting of nanoparticles of indium tin oxide (i.e., In(2)O(3):Sn) with f close to the percolation limit. It showed that the as-deposited film contained nanoparticles with n(e) as large as similar to5x10(20) cm(-3) and rhoapproximate to5x10(-4) Omega cm. The model also provided important data on f, n(e), and rho after heat treatment of the film. (C) 2003 American Institute of Physics.