Enhanced metal–insulator transition in V2O3 by thermal quenching after growth

The properties of oxides are critically controlled by the oxygen stoichiometry. Minimal variations in oxygen content can lead to vast changes in their properties. The addition of oxygen during synthesis may not be a precise enough knob for tuning the oxygen stoichiometry when the material has several stable and close oxidation states. We use sputtered V2O3 films as an example to show that rapid transfer of the sample away from the heating element after growth causes a temperature decrease (quenching) quick enough to freeze the correct oxygen stoichiometry in the sample. This procedure has allowed us to improve dramatically the V2O3 electronic properties without any adverse measurable effects on the structural properties. In this fashion, the metal–insulator transition resistance change was increased by two orders of magnitude, while the transition width was decreased by 20 K.