Effect of N+ ion implantation on the optical properties of nanostructured CdS thin film prepared by CBD technique

Nanostructured CdS thin films were deposited on glass substrates by chemical bath deposition technique. RBS and SEM analyses showed that the film surface was smooth, consisting of uniformly dispersed clusters. Absorption spectra of as prepared sample showed a blue shift in the absorption edge indicating quantum confinement effect. The band gap of the N+ ion implanted samples decreased with increase in implantation fluence. Photoluminescence spectra showed a new peak (red band), in addition to the violet, blue and yellow emissions, due to surface states created during ion implantation. Raman peak appearing at 300 cm−1 for both as deposited and N+ ion implanted samples was attributed to A1(LO) phonon of CdS. A new Raman peak which appeared at 250 cm−1 in the case of N+ ion implanted samples was interpreted as E1(TO) mode resulting from the lattice disorder occurred due to ion implantation. The ratio of intensity of E1(TO) mode to that of A1(LO) mode showed conspicuous increase with increase in implantation fluence and the FWHM of both the modes increases with increase of implantation fluence.