Transparent conducting oxide thin films of Cd2SnO4 prepared by RF magnetron co-sputtering of the constituent binary oxides

Thin films of cadmium tin oxide (Cd2SnO4) have been deposited on glass substrates by RF magnetron co-sputtering from cadmium oxide (CdO) and tin oxide (SnO2) targets in an Argon ambient. Co-sputtering offers a means to control the atomic stoichiometry of Cd2SnO4, which influences the material's electro-optical and structural properties. The Cd2SnO4 films were deposited at room temperature and subsequently subjected to a heat treatment in inert or reducing (H2) ambient. The as-deposited films were amorphous, and became polycrystalline after annealing at high temperatures. Using this method, Cd2SnO4 films with a Hall mobility of 32.3 cm2 V−1 s−1 and a carrier concentration of 7.40×1020 cm−3 corresponding to a resistivity of 2.07×10−4 Ω cm have been prepared. The films exhibited average optical total transmission in excess of 90% in the visible region. The optical bandgap was found to be in the range of 2.97-3.18 eV, depending on post deposition treatment.