Spectroscopy of individual silicon nanowires

Photoluminescence (PL) spectroscopy of individual silicon nanowires has been investigated. A narrow emission band (85 meV) was observed associated with a fast luminescence decay in the picosecond region and is considered due to the recombination relaxation of confined electronic states. The optical anisotropy was found in the individual nanowires. When a wire was excited by linearly polarized light, the maximum intensity of linearly polarized PL was along the axis direction of the wire, and the maximum degree of polarization was determined to be 0.5. The value agrees well with the calculated one, which suggests that the polarization arise from the dielectric contrast between the crystalline cores and the silicon oxide sheathes of the nanowires. (C) 2003 American Institute of Physics.