Vacuum-evaporated metal-free alpha-phthalocyanine films sandwiched between two gold electrodes have been prepared and their photoelectrical properties studied in vacuo (5 x 10(-4) Pa). The density of the films depends on their thickness : the thicker the film, the lower the mean density of the material. The geometrical non-uniformity along the direction perpendicular to the substrate plane results in the formation of a spatial trap distribution which influences the built-in field and the magnitude of the open circuit voltage induced by sample irradiation.