Chemical nitridation of GaAs(100) by hydrazine-sulfide water solutions

We have developed for GaAs a new nitrogen chemical surface passivation. The passivation procedure that can be justified from chemical reasonings, consists of a wet treatment by a mixture of hydrazine and sodium sulfide solutions, and is proposed to produce an essentially Ga-terminated (1 0 0) surface covered with a monolayer of chemisorbed nitrogen. The as-treated surface reveals clear (1 x 1) RHEED pattern that confirms the formation of the thin and coherent GaN him. The chemical nitridation of GaAs surface produces an increase of photoluminescence intensity. This effect is found to be stronger and more stable in air ambient under above band-gap light excitation than that produced by sulfide passivation. (C) 2000 Elsevier Science Ltd. All rights reserved.