SERS based detection of Dichlorvos pesticide using silver nanoparticles arrays: Influence of array wavelength/amplitude

Ion beam irradiation produced ripple nanopatterns on Si surface was used to produce a highly dense and sensitive SERS substrate for detecting Dichlorvos pesticide below the permissible limit. The wavelength of the ripple varied from 22 nm to 35 nm by changing ion beam energy from 200 eV to 500 eV. Highly regular nanoparticles arrays were produced down to 22 nm wavelength choosing the proper ion beam parameter and ripple orientation during deposition. The shape of deposited nanoparticles on ripple nanostructures changed from elongated to spherical upon increasing wavelength and amplitude of ripples at different ion energies. The optimization of SERS intensity was carried out using crystal violet dye which revealed that the maximum enhancement (enhancement factor similar to 10(7)) occurred for the 300 eV irradiated substrate. The optimized substrate was used for detecting Dichlorvos up to 1 ppm level without using any binder molecule.