Enhancement of porous silicon photoluminescence using vanadium pentoxide (V2O5) treatment

A new method has been developed to improve the photoluminescence intensity of porous Silicon PS. In this treatment we used vanadium, for the first time, to passivate porous silicon. Thermal evaporation of (onto PS layer, followed by a thermal treatment at 100 degrees C, 200 degrees C, 300 degrees C and 400 degrees C for 15 min under oxygen flow, can increase the intensity of the photoluminescence of PS. Vanadium oxide covers the nanoparticles of silicon without changing the wavelength distribution of the optical excitation and emission spectra. Changes in the surface morphology induced by thermal treatment were investigated by atomic force microscope (AFM) showing an increase of the nanoparticles dimensions compared to the initial dimensions of the PS nanostructure. The reflection spectra of PS, before and after treatment with (V2O5), performed in the 300-1200 nm wavelength range and compared to a virgin mc-Si wafer, showed an important decrease of the reflectivity by this new treatment.