TY - JOUR
T1 - Ultrafast Terahertz Conductivity of Photoexcited Nanocrystalline Silicon
AU - Cooke, David
AU - MacDonald, A. Nicole
AU - Hryciw, Aaron
AU - Meldrum, Al
AU - Wang, Juan
AU - Li, Q.
AU - Hegmann, Frank A.
PY - 2007
Y1 - 2007
N2 - The ultrafast transient ac conductivity of nanocrystalline silicon films is investigated using time-resolved terahertz spectroscopy. While epitaxial silicon on sapphire exhibits a free carrier Drude response, silicon nanocrystals embedded in glass show a response that is best described by a classical Drude–Smith model, suitable for disorder-driven metal–insulator transitions. In this work, we explore the time evolution of the frequency dependent complex conductivity after optical injection of carriers on a picosecond time scale. Furthermore, we show the lifetime of photoconductivity in the silicon nanocrystal films is dominated by trapping at the Si/SiO2 interface states, occurring on a 1–100 ps time scale depending on particle size and hydrogen passivation
AB - The ultrafast transient ac conductivity of nanocrystalline silicon films is investigated using time-resolved terahertz spectroscopy. While epitaxial silicon on sapphire exhibits a free carrier Drude response, silicon nanocrystals embedded in glass show a response that is best described by a classical Drude–Smith model, suitable for disorder-driven metal–insulator transitions. In this work, we explore the time evolution of the frequency dependent complex conductivity after optical injection of carriers on a picosecond time scale. Furthermore, we show the lifetime of photoconductivity in the silicon nanocrystal films is dominated by trapping at the Si/SiO2 interface states, occurring on a 1–100 ps time scale depending on particle size and hydrogen passivation
U2 - 10.1007/s10854-007-9248-y
DO - 10.1007/s10854-007-9248-y
M3 - Journal article
SN - 0022-2461
JO - Journal of Materials Science
JF - Journal of Materials Science
ER -