Self-assembled flower-like microstructure in Zn 1-x Cd x O nanoparticles

Abstract

The structural and optical characterization of cadmium-doped zinc oxide nanoparticles synthesized by precipitation method was studied. X-ray diffraction study confirmed the substitution of cadmium dopant without disturbing the basic wurtzite structure of zinc oxide. The average crystalline size, lattice constants and unit cell volume also increased up to 4% of cadmium doping. Energy gaps of the samples were determined from the ultraviolet-visible absorption spectrum as well as Tauc's plot which infers that the energy gap decreases with the increase of cadmium content. Fourier transformation infrared spectrum confirms the cadmium dopant through peak shifting from 485 to 563 cm−1. Photoluminescence spectrum also defines the cadmium dopant by intensity increase. The broad Raman peak at 437 cm−1 indicates that the wurtzite structure of zinc oxide is weakened by 5% cadmium doping. Field emission scanning electron microscope study also confirms the existence of particles in nanometer size and it indentifies the microstructure transformation from nanoparticles to jasmine flower-like structure on 5% cadmium doping.