The terahertz conductivity of silicon nanoparticles embedded in glass with varying density is studied with ultra-broadband terahertz spectroscopy on picosecond time scales following fs optical excitation. The transition from relatively isolated charge carriers to densities which allow inter-particle transport is clearly observed. For the times immediately following carrier injection, we observe Drude-like long range transport that is rapidly replaced with a localized response on picosecond time scales. The localized response can be very well described by a phenomenological Drude-Smith model, verifying the applicability of this simple model to the conductivity of nanoparticle ensembles over the entire THz spectral window.
Bibliographical noteCopyright (2012) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in
Applied Physics Letters / Volume 101 / Issue 21 and may be found at http://apl.aip.org/resource/1/applab/v101/i21/p211107_s1.