Thermoelectric properties of CaMnO3 films obtained by soft chemistry synthesis

Polycrystalline randomly oriented CaMnO3 films were successfully deposited on sapphire substrates by soft chemistry methods. The precursor solutions were obtained from a mixture of metal acetates dissolved in acids. The Seebeck coefficient and the electrical resistivity were measured in the temperature range of 300 K, T, 1000 K. Modifications of thermal annealing procedures during the deposition of precursor layers resulted in different power factor values. Thermal annealing of CaMnO3 films at 900 degrees C for 48 h after four-layer depositions (route A) resulted in a pure perovskite phase with higher power factor and electrical resistivity than four-layer depositions of films annealed layer by layer at 900 degrees C for 48 h (route B). The studied films have negative Seebeck coefficients indicative of n-type conduction and electrical resistivities showing semiconducting behavior.