A simple method of separating the opposing photocurrent components which occur in thin‐film, metal‐insulator‐metal sandwich structures at low (or zero) applied bias voltages is presented. The method uses data obtained by illuminating the sample first from one side and then from the other, both electrodes being semitransparent, and calculating the ratio of the resulting photo‐yields over a suitable photon energy range. The analysis has been applied to evaporated Al‐Al3O3‐Al diodes in which the Al2O3layer was formed by evaporation of sapphire. The experimental results show that the proposed analysis is adequate for its intended purpose.