A ZnS thin film was electrodeposited on the surface of nanopores of porous silicon (PSi) without plugging of the nanopores. And the optical properties of the ZnS/PSi composites were investigated. The PSi was fabricated by anodization of n-Si (100) wafer in HF/EtOH/H2O solution under constant current conditions. The pore diameter and the porous layer depth of the PSi were 20-80 nm and 8-50 mm, respectively, and they are controlled by variation of the HF concentration and anodization time. Electrodeposition proceeded on the surface of the nanopores (pore diameter, 80 nm) of the PSi under galvanostatic conditions of 0.44-8.85 mA/cm(2) and the aqueous electrolyte solution contained ZnSO4, Na2S2O3 and glycerol. The deposited ZnS plugged the nanopores at high current density, whereas at low current density, ZnS was deposited on the nanopore wall without plugging. The photoluminescence (PL) spectra due to the ZnS/PSi composites showed two separate peaks at 430 nm and 530 nm. The PL intensity decreased with increased current density because of the segregation of ZnS on the upper parts of the PSi nanopores. The PL intensity was also enhanced owing to the large surface area of the PSi. (C) 2016 Elsevier Ltd. All rights reserved.