Array-ordered silicon nanowires (SiNWs) were fabricated directly on p-Si substrate by wet chemical etching. The as-prepared SiNWs apparently were composed of a single-crystalline Si core embedded in an amorphous SiO2 shell (similar to 5 nm). Raman spectra indicated that the surface of as-prepared SiNWs contained a collection of smaller Si crystalline nanograins. The characteristic peaks induced by Si nanograins were observed in the Raman and photoluminescence (PL) spectra due to the quantum confinement effect. The study revealed that the array-ordered SiNWs would have a great potential of application in nanoscale electric and optoelectronic devices by controlling the fabrication processes. (C) 2011 Elsevier B.V. All rights reserved.