Strong enhancement of the optical properties of SiNWs by the deposition of snowball-like V2O5 nanoparticles

Abstract

In this work, the morphological and optical properties of vanadium pentoxide (V2O5) nanoparticles deposited on silicon nanowires (SiNWs) have been investigated. SiNWs are obtained by metal-assisted chemical etching (MACE) method. The deposition of vanadium pentoxide on SiNWs layer was performed by vacuum thermal evaporation system for different durations. Scanning electronic microscope (SEM) images show the formation of snowball-like V2O5 nanoparticles on the SiNWs surface. A large condensation of V2O5 elements was observed by increasing the evaporation time. The changes in bonds and chemical composition at the surface of the SiNWs-V2O5 nanocomposites were examined by Raman and Fourier transform infrared (FTIR) spectroscopies. The X-ray Diffraction (XRD) technique revealed the presence of orthorhombic structure of V2O5 layer with good crystallinity. The SiNWs-V2O5 composites show strong visible PL due to the contribution of the radiative band edge transitions of vanadium pentoxide. The emission of V2O5 layer is in the same energy range as that of SiNWs thus leading to a large increase in PL intensity. Optical band gap (Eog) was determined from UV–Vis-IR spectroscopy. The presence of vanadium pentoxide on the SiNWs surface causes an increase in the value of Eog from 1.851 to 2.075 eV. This increase was explained by Burstein-Moss effect.