synthesis and characterization of al doped and (co, al) codoped zno nanoparticles via chemical co-precipitation method

Pure, al doped, and (co, al) co-doped zno nano-powders were synthesized through chemical co-precipitation method at room temperature, using poly ethylene glycol (peg) as stabilizing agent. the synthesized samples are characterized by x-ray diffraction (xrd), scanning electron microscopy (sem) & energy-dispersive x-ray spectroscopy (eds), transmission electron microscopy (tem), high resolution transmission electron microscopy (hrtem), the selected area electron diffraction (saed) and vibrating sample magnetometer (vsm). xrd results revealed that all the samples had a hexagonal wurtzite crystal structure with no secondary phases and this indicates the absence of superfluous impurities. (co, al) co-doped samples reveals the lowest crystallite size comparing to pure and al doped zno nano-particles, doping of aluminum and cobalt, aluminum could not disturb the wurtzite structure of zno host lattice. sem analysis demonstrated the morphology of the pure, al doped, and (co, al) co-doped zno nano-particles, morphology of the (co, al) co-doped samples shows high agglomeration compared to pure and al-doped zno nano-particles. eds spectrum shows the incorporation of dopant elements, it reveals the nonexistence of impurities other than zn, al, and co which is coincided by xrd results. tem illustrations reveal the exact size of the crystallites, which are approximately confirmed by the xrd data, tem images obviously shows that nano-particles are in heterogeneous spherical shape. hrtem images of the pure and al-doped zno nano-particles shows clear lattice fringes about 5 nm and (co, al) co-doped images reveal lattice fringes are about 2 nm. vsm analysis of (co, al) co-doped samples reveals that all the three (1, 2, 3 mol% of cobalt by keeping al-5 mol% at constant) concentrations showed the ferromagnetic nature at room temperature. among these 1 mol % of cobalt shows highest saturation magnetization (ms) and retentivity (mr) values, while 2 mol % of cobalt shows highest coercitivity (hc) value.