Nonuniform current‐carrier mobility‐induced bulk photovoltaic effect in bounded semiconductors

The photo-emf and the short-circuit photocurrent in a closed circuit consisting of a bipolar semiconductor with uniform electron and hole dark densities, but inhomogeneous electron mobility is theoretically studied with emphasis on the influence of the boundary conditions on the photo-emf magnitude. It is shown that the photocurrent vanishes in the closed circuit when the entire semiconductor is uniformly illuminated, while the presence of a metal region in the circuit enables the photocurrent generation. The functional dependence of the photo-emf on the sample size and the current-carrier diffusion length is investigated. The physics of the effect and its relation to the Dember photoeffect and the bulk photovoltaic effect is also discussed.