Electronic Transport in Amorphous Silicon Films

Abstract

Drift mobility and conductivity measurements were made between 290 and 85\ifmmode^\circ\else\textdegree\fi{}K on amorphous silicon specimens prepared by glow-discharge decomposition of silane. The results suggest that excess electrons drift in the extended states with a mobility of about 10 ${\mathrm{cm}}^{2}$ ${\mathrm{sec}}^{\ensuremath{-}1}$ ${\mathrm{V}}^{\ensuremath{-}1}$. At lower temperatures, phonon-assisted hopping occurs through localized states occupying a range of 0.2 eV below the extended states. Conductivity results also suggest hopping transport near the Fermi energy.