Photoelectrochemical Analysis of Doped Hydrogenated Amorphous Silicon

Abstract

Photoelectrochemical techniques have been employed in an analysis of p‐ and n‐doped, hydrogenated amorphous silicon (a‐Si) and hydrogenated amorphous silicon carbide alloy films false(normala‐normalSiCfalse) . Materials with a range of doping densities were examined. Flatband potentials of n a‐Si and normalp a‐normalSiC electrodes were determined and used to predict the maximum photovoltage attainable from a composite p‐i‐n structure made from these films. Energy gaps for optical absorption and photocurrent production were also measured, and the relationship of the energy gap for photocurrent to the mobility gap of these materials is discussed. An optical interference effect in these thin film electrodes was used to deduce the effective doping density of the n‐type materials. Electrochemical measures have been established to quantify the extent of defects in the films caused by the low doping efficiencies of the dopant gases.