Effects of Localized Surface Charges on a Two-Dimensional Potential Distribution and Photovoltage at a Schottky Barrier of a Semiconductor Electrode

Abstract

Although experimental studies have long been reporting the importance of a beneficial effect of a metal nanodot coating of a semiconductor electrode for solar energy conversion, little theoretical work has been done on quantitative analysis of the effect most probably because of mathematical difficulty in calculating a two-dimensional potential distribution in the space charge layer induced by localized surface modifications or charges. This paper reports a simple method for calculating such a two-dimensional potential distribution and clarifies how the Schottky-barrier height (or flat-band potential) is affected by localized surface charges of various sizes and separations. The results not only give an unambiguous theoretical basis to the beneficial effect of a nanodot coating but also provide effective information for analysis of kinetics in semiconductor devices with nanostructures.