Effect of negative aluminium ion implantation in the properties of CdSe nanowires

The effect of negative ion implantation on the 80 nm diameter cadmium selenide (CdSe) nanowires is investigated in the present study. Nanowires were electrodeposited by potentiostatic method using polycarbonate membranes as template. These nanowires were implanted with 200 keV negative aluminium ions of single charge state at different fluence ranging from 1011 to 1013 ions/cm2. Implantation effects on the wires were studied using different characterizations like X-ray diffraction, optical absorption, energy dispersive spectroscopy, current-voltage characteristics curve and impedance measurements. XRD and EDS analysis confirmed the formation of CdSe nanowires in the pristine case and the presence of aluminium in the implanted samples. Shifting in the positions of the diffraction peaks was not observed on implantation, however an intensity variation and an additional peak of very low intensity, corresponding to aluminium was observed. Increment in the crystallite size and a red shift in the optical band gap were also noticed after implantation as the fluence was increased. Both I-V curves and impedance measurements revealed an enhancement in the conductivity of post ion implanted samples. This may be attributed to the availability of more charge carriers, localized heating and coalescence of grains as a result of ion implantation.