The tunnel-current and photon-induced current in nanoscale photovoltaics

Abstract

Abstract In this work, the photo-induced current in a nanoscale photovoltaic device consisting of a quatum dot (QD) that is coupled to two metallic electrodes is derived by using the nonequilibrium Green function (NEGF) technique. The QD is assumed to have two levels and only one of them is within the bias window. The dependence of photocurrent on the photon’s energy and the level widths is analysed. This study shows the photocurrent could be maximized for a given range of photons’ energy which relates to the gap between levels and the level widths.