PHOTOLUMINESCENCE AT A SEMICONDUCTOR ELECTROLYTE CONTACT AROUND AND BEYOND THE FLAT-BAND POTENTIAL

Photoluminescence measurements have been performed to study CdSe-, CdS-, and GaP-electrolyte contacts under cathodic bias. A strong increase of the luminescence intensity has been found in those cases where an accumulation layer is formed at the interface. This potential dependence is interpreted in terms of a quenching of surface recombination by the repulsive field in the space charge region which impedes the minority carriers to reach the surface. A theoretical description based on the Stevenson-Keyes approach for recombination is derived by introducing an exponential potential dependence of the surface recombination rate into the calculations of the luminescence generation in the bulk of the semiconductor. © 1990 American Chemical Society.