  Photoconductivity of single-crystalline selenium nanotubes (SCSNT) under a
range of illumination intensities of a 633nm laser is carried out with a novel
two terminal device arrangement at room temperature. It's found that SCSNT
forms Schottky barriers with the W and Au contacts, and the barrier height is a
function of the light intensities. In low illumination regime below 1.46x10E-4
muWmum-2, the Au-Se-W hybrid structure exhibits sharp switch on/off behavior,
and the turn-on voltages decrease with increasing illuminating intensities. In
the high illumination regime above 7x10E-4 muWmum-2, the device exhibits ohmic
conductance with a photoconductivity as high as 0.59Ohmcm-1, significantly
higher that reported values for carbon and GaN nanotubes. This finding suggests
that SCSNT is potentially a good photo-sensor material as well we a very
effective solar cell material.
