Highly oriented silicon nanowire (SiNW) layer was fabricated by etching Si substrate in HF/(AgNO3 + Na2S2O8) solution at 50 degrees C. The morphology and the photoluminescence (PL) of the etched layer as a function of Na2S2O8 concentration were studied. The SiNW layers formed on silicon were investigated by scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). It was demonstrated that the morphology of the etched layers depends on the Na2S2O8 concentration. Room-temperature photoluminescence (PL) from etched layer was observed. It was found that the utilisation of Na2S2O8 decreases PL peak intensity. Finally, a discussion on the formation process of the silicon nanowires is presented. (C) 2008 Elsevier B.V. All rights reserved.