In this paper, we investigated the morphological, optical and electrical properties of sol-gel spin coated ZnS film and device performance of fabricated Al/ZnS/p-Si/Al heterojunction diode. AFM images showed that surface morphology of the film was smooth which had 2.17 nm surface rougness, almost homogenous and dense. The optical band gap value of the ZnS film was found to be 3.83 eV. From electrical studies, it was found that Al/ZnS/p-Si/Al heterojunction diode showed a rectification behavior; and its ideality factor, barrier height and the series resistance values were calculated to be 2.34, 0.77 eV and 12.3-12.5 k Omega respectively. The results show that Al/ZnS/p-Si/Al diode is successfully fabricated using the sol-gel spin coating technique. (c) 2013 Elsevier B.V. All rights reserved.