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Aligned TiO2 nanowire arrays were fabricated onto Si wafers by a simple thermal deposition (PVD) method. Scanning electron microscopy and high-resolution transmission electron microscopy observations confirm that the as-prepared TiO2 nanowires are single-crystalline and of high purity. Field emission measurements showed that the TiO2 nanowire arrays could provide stable, high-current electron emission at a low voltage. The emission current monitored over a period of 24 h fluctuated gently but did not show degradation. The cathode-luminescence (CL) images captured by a CCD camera were very bright and their CL intensity was homogeneous. This remarkable performance reveals that TiO2 nanowire arrays are well suited for commercial use in electron devices, particularly flat panel displays. [ABSTRACT FROM AUTHOR]

Patterned gallium nitride nanowires have been grown on n-Si(100) substrates by pulsed laser ablation. The nanowires are patterned using a physical mask, resulting in regions of nanowire growth of different density. These gallium nitride nanowires are single-crystalline with hexagonal wurzite structures. The electrical transport measurements of individual GaN nanowires show near-linear current-voltage characteristics. The estimated electron densities of these individual GaN nanowires range from 1.8-6.8 x 1018 cm[?]3. The field emission characteristics of these patterned gallium nitride nanowires show a turn-on field of 8.4 V um[?]1 to achieve a current density of 0.01 mA cm[?]2 and an enhanced field emission current density as high as 0.96 mA cm[?]2 at an applied field of 10.8 V um[?]1. The field emission results indicate that, besides crystalline quality as well as the low electron affinity of gallium nitride, density difference in the nanowires growth greatly enhances their field emission properties by reducing the screening between nanowires. [ABSTRACT FROM AUTHOR]