Characterization of Nanocones Grown During DC Magnetron Sputtering of an ITO Target
AbstractA low temperature method for uniform growth of In2O3 nanostructures on Si wafers that does not require separate catalyst materials or template-assistance is investigated. Nanostructures are uniformly deposited on either bare or SiO2 thin film coated Si substrates via DC magnetron sputtering at 200-400°C using a 90% In2O3 / 10% SnO2 (ITO) target. The nanostructures are approximately 500 nm long, sit atop an accompanying underlying 100 nm conductive film, and are conically shaped, with a diameter of about 80 nm at the base, tapering to a point that is capped with a spherical “ball”. X-ray diffraction (XRD) indicates a cubic In2O3 phase. Field emission from the tips is observed at a base pressure of 10-8 Torr with turn-on fields in a range between 45-75 V/cm and threshold fields from 64-105 V/cm. Nanocone growth is investigated with respect to O2 and Ar flow rates, temperature, power, pressure, wafer rotation, and time.