In this study, the effect of the incorporation of ZnO nanoparticles into poly(3-hexylthiophene) (P3HT) on photocurrent of P3HT/n-type Si diodes was examined. Charge detrapping/trapping phenomena are studied through time domain measurement for P3HT-based diodes and thin-film transistors. Hole detrapping was the dominant phenomena in P3HT (ZnO-doped P3HT) films. For higher density of ZnO, more holes can be released and induce higher photosensitivity of the device. ZnO influences the photoresponse by providing additional holes that serve to reduce the photocurrent time constant. (C) 2013 Elsevier B.V. All rights reserved.