X-ray photoemission spectroscopy analysis of Si(111) under photocurrent-doubling conditions

Abstract

In this study we present the first results of surface-analytical measurements on (111)-oriented n-type crystalline silicon subjected to photocurrent doubling. In an aqueous solution of 1M ${\mathrm{NH}}_4$F at pH 5.3, photocurrent doubling was established under low-intensity illumination. Subsequent x-ray photoemission spectroscopy analysis shows the presence of dissociatively adsorbed water (≊1 monolayer) together with submonolayer amounts of a Si-${\mathrm{F}}_{\mathrm{x}}$ (x≥2) species at the surface in accordance with existing models of photocurrent multiplying by electron injection via intermediate Si-F surface complexes.