Growth parameter-property phase diagram for pulsed laser deposited transparent oxide conductor anatase Nb:TiO2

The authors performed a systematic study of the structural and electrical properties of Nb:TiO2 thin films by varying the substrate temperature (T-S) and oxygen partial pressure (P-O2). Niobium is found to incorporate easily and substitutionally into titanium lattice site as indicated by its low activation energy. By increasing T-S, the carrier concentration (n) increases in the same way that niobium substitution fraction (s) increases, and the mobility increases as the structural quality is improved. With increasing P-O2, n decreases dramatically though s does not change considerably. This may indicate that a large number of p-type native defects form, which "kill" the electrons produced by the Nb donors.