Optical and Electric Properties of Aligned-Growing Ta2O5 Nanorods

These vertically aligned Ta2O5 nanorods were deposited on Si (100) substrates by thermal deposition in a vacuum of the order of 10(-2) Torr at about 600 degrees C. When excited by 514 nm Ar+ laser, they showed a strong photoluminescence at similar to 622 nm, which was attributed to the oxygen vacancies. In addition, their dielectric constant is similar to 20 in the frequency range from 1 kHz to 10 MHz, far larger than that of SiO2 and Si3N4. Due to this cone-shaped morphology, the Ta2O5 nanorods exhibited a threshold field of similar to 8.5 V/mu m in field emission and a field enhancement factor of 764 that are sufficiently high for field emission application. [doi: 10.2320/matertrans.MRA2008137]