Photoelectron Spectroscopy of Individual Si Nanowires

We describe an experiment designed to investigate the electronic structure of individual nanowires of Si. Laser generated 150 femtosecond pulses of photons with a wavelength of 200 nm (6.2 eV) were focused onto an individual Si nanowire. Photoelectrons emitted from the wire were collected and energy analyzed by an electrostatic spectrometer with 20 meV resolution. Si wires, grown across gaps on a lithographically patterned substrate, exhibited diameters that varied between 20 and 400nm depending on growth conditions. In these experiments we have observed strong polarization dependent electron emission consistent with Mie theory. We have measured the location of the Fermi level within the intrinsic Si wire band gap, the work functions of individual hydrogen terminated wires, which are compared with those of Ge nanowires, and observed polarization dependent spectral features. Variations in spectral features from wire-to-wire are suggested to derive from size dependent growth directions and faceting.

By: Richard Haight; George Sirinakis, Mark Reuter

Published in: RC24263 in 2007

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