Sulphide passivation of GaAs: the role of the sulphur chemical activity

Abstract
The passivation of n-GaAs in different sulphur containing solutions in which sulphur chemical activity was varied, i.e. solutions of sodium and ammonium sulphides in water and alcohols, as well as a solution of sulphur monochloride in carbon tetrachloride, was studied by photoluminescence and Raman spectroscopy. The increase of the sulphur chemical activity in the passivating solution results in an increase of the photoluminescence intensity and in a decrease of the surface barrier of the passivated semiconductor.