Processing parameters and transport properties of vacuum-evaporated CdSe thin films

CdSe films were thermally deposited on glass substrate at different of substrate temperatures and deposition rates and ambient pressures below 10(-3) Pa. Resistivity and Hall effect parameters were investigated in either as-deposited films as well as samples annealed at 670 K under vacuum. Measurements were performed in the temperature range 140 K - 670 K. These properties were found to be related to the deposition conditions. It was found that Hall mobility increases when the substrate temperature decrease or the deposition rate increases. The Hall mobility was interpreted in terms of the Petritz inter-crystalline barrier model in which it is thermally activated and follows the relation mu(H) = mu(o) exp (- E/kT). Thus, it is not only determined by scattering mechanisms but also by the number and properties of potential barriers at the crystallites boundaries. The resistivity and electron concentration increases with increasing temperature what indicates a self-activated conductivity mechanism.