Electrical and optical properties of ferric pride thin films prepared via a sol-gel method

The sol-gel process has been employed for depositing hematite films on vari ous substrates. These films were characterized by structural, electrical, a nd optical techniques. Dip coating produced films 100 nm thick comprising n anoparticles of size 20 nm with a yellow color and good adhesion to a glass substrate. Electrical conductivity measurements showed a thermal activatio n energy, E-a, of 0.82 eV, a hopping activation energy, w, of 0.86 eV, and a thermal activation energy of mobility, E-mu, of 0.04 eV. The optical stud ies demonstrated an increase in transmittance to >90%, a decrease in reflec tance to <10%, and a sharp edge at <similar to>600 nm. An absorption coeffi cient, alpha, of 10(4) cm(-1), an allowed direct type transition of 2.63 eV , an indirect type transition of 1.95 eV, and an absorption index, k, from 0.05 to 2 were estimated. (C) 2001 Elsevier Science Ltd. All rights reserve d.