In this paper we find the microscopic mechanism of persistent photoconductivity in doping‐modulated amorphous silicon superlattices is the same as that of compensated amorphous silicon. The carrier separation due to a built‐inn‐pjunction field can explain persistent photoconductivity in compensated amorphous silicon films. This new analysis is favored by experimental results on the persistent photoconductivity in compensated as well as in layered amorphous silicon films.