Processing and properties of centimeter-long, in-fiber, crystalline-selenium filaments

We report on the fabrication and characterization of globally ordered crystalline selenium filaments with diameters about 200 nm and aspect ratios upwards of 10⁵. Amorphous Se filaments are fabricated by a recently developed approach in which a thin film evolves into an ordered array of filaments in fiber. Single-crystal and polycrystalline filaments are attained with a postdrawing annealing procedure. Arrays of two-cm-long crystalline nanowires, electrically contacted to external circuitry through the fiber end facets, exhibit a two-orders-of-magnitude change in conductivity between dark and illuminated states. These results hold promise for the fabrication of filament-detector arrays that may be integrated with large-area electronics.