Films of ZnS have been deposited by rf sputtering and subsequently implanted with Al. Examination of the conductivities, after annealing, shows that Al is effective in decreasing the film resistivity. At ∼ 300 K the room‐temperature conductivity could be reduced to 10−2&OHgr;−1 cm−1compared with 10−10&OHgr;−1 cm−1in undoped films. The small activation energy of ∼ 0.1 eV of the electrical conductivity and the temperature dependence of the thermoelectric power may possibly be indicative of impurity conduction.