The present work accentuates the effect of UV laser irradiation on the conductivity of nickel oxide (NiO) thin films, deposited at various temperatures by radio-frequency reactive sputtering of Ni in oxygen containing atmosphere. The effect of UV irradiation on zinc oxide – nickel oxide heterostructures, obtained by sputtering, was examined as well. It was found that the resistivity of NiO changes from 12 Ω-cm to 0.62 Ω-cm, and the majority carrier concentration from 3.95x1017 holes/cm3 to 4.22x1020 electrons/cm3. The current-voltage (I-V) characteristics of the ZnO/NiO heterostructure shows an improved p-n diode behavior with the forward bias current increasing for the laser-irradiated ZnO/NiO compared to the as-deposited stack. The observed improvement in diode-like behavior suggests that laser irradiation can be an important technique to controllably change the structural, electrical and optical properties of metal oxide thin films.