Selective (photo)electrochemical etching of semiconductor surfaces

Abstract The performance and output stability of various photoelectrochemical solar cells can be improved considerably by a short photoelectrochemical etching of the semiconductor surface. This paper describes the experimental work which is involved in the research of that phenomenon. A unique morphological pattern is observed on the surface of photoetched semiconductors. This pattern consists of a dense network of submicron pits. We argue that this pattern is a result of discrete dopant atoms (or vacancies), which either influence the space charge layer field in their vicinity, leading to non-homogeneous hole flow to the surface, or, what is more likely still, the dopant atoms at or near the surface are preferentially attacked by the holes. In this case, each pit represents the position of a former dopant atom or vacancy. This hypothesis is in accord with the observed pit density at the surface.

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