ZnO:Al/p-Si heterojunctions were fabricated by solgel dip coating technique onto p-type Si wafer substrates. Al-doped zinc oxide (ZnO:Al) thin film on p-Si wafer was irradiated by reactor neutrons at ITU TRIGA Mark-II nuclear reactor. Neutron irradiation was performed with neutron/gamma ratio at 1.44 x 10(4) (n cm(-2) s(-1) mR(-1)). The effect of neutron irradiation on the electrical characteristics of the ZnO: Al thin film was evaluated by means of current-voltage (I-V) characteristics for the unirradiated and the irradiated states. For this purpose, the changes of I-V characteristics of the unirradiated ZnO: Al thin films were compared with the irradiated ZnO: Al by reactor neutrons. The irradiated thin ZnO: Al film cell structure is appropriate for the usage of solar cell material which is promising energy material.