Effect of Ni-doping concentration on structural, optical and magnetic properties of CdSe nanorods

Cd1−xNixSe (x=0.00, 0.05, 0.10 and 0.15) nanorods have been synthesized using solvothermal route. X-ray diffraction (XRD) studies show that the nanorods possess wurtzite phase having hexagonal structure. Transmission electron microscopy (TEM) reveals the formation of nanorods having lengths 150–200 nm and diameters 10–15 nm. This has been further confirmed by high-resolution transmission electron microscopy (HRTEM) wherein lattice fringes corresponding to CdSe have been well observed. Reflectance measurements illustrate the red-shift in band gap with increase of Ni-doping concentration. Raman spectra display the shifting of longitudinal optical (LO) phonon modes, and modes activation due to doping in CdSe nanorods. Magnetic hysteresis (M–H) loops at room temperature reveal the ferromagnetism in nanorods. The saturation magnetization values have been observed to increase upto 10% due to carrier mediated exchange interactions, whereas a decrease has been observed for 15% Ni-doping concentration due to super-exchange interactions.