SURFACE-REACTIONS AT P-TYPE AND N-TYPE ZNSE IN AQUEOUS-SOLUTIONS

The surface chemistry of epitaxially grown p-type and n-type ZnSe in a queous solutions was studied by photoelectrochemical methods. The firs t measurements on p-ZnSe in indifferent electrolyte solution show typi cal semiconductor electrode properties: dissolution of the solid in th e dark at positive potentials and reduction of water to hydrogen under illumination at negative potentials. The influence of band gap mismat ch between ZnSe and the GaAs substrate is clear for the n-type semicon ductor. From a comparison of results obtained with p-type and n-type Z nSe electrodes at pH 7.0, it is concluded that the electrochemical red uction of hypochlorous acid occurs via the conduction band of the semi conductor. It is shown that ZnSe is etched chemically in hypochlorous acid solution and that selective etching with respect to the GaAs subs trate is possible.