Mn-Doped ZnO Micro and Nanocrytals: Synthesis, Characterization and Properties

Abstract

The development of highly sensitive, selective, reliable, low power and compact sensing devices to detect gas is of major importance for terrestrial and space applications. The gas response to different gases and chemicals is related to a great extent to the surface state and morphology of the materials. Zinc oxide (ZnO) is a direct wide band gap semiconductor with an energy gap of ~3.37 eV and a large exciton binding energy of ~60 meV at room temperature (RT) is a promising candidate for functional component for devices and materials in chemical and gas sensors and so on. ZnO nanostructures with various interesting structures and properties have been synthesized, such as nanoparticles, nanorods, nanobelts, nanocombs, nanowires, tetrapod nanostructures. Mn-doped hexagonal (ZnO) semiconductor micro and nanostructures have been synthesized by a simple one-step aqueous solution method at relatively low temperature. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and photoluminescence spectroscopy (PL) have been used to characterize the samples in detail. The XRD studies revealed that Mn doped ZnO micro and nanostructures had wurtzite structure (hexagonal). The as-synthesized ZnO micro and nanostructures consist of very uniform and no secondary phase is observed. X-ray diffraction and EDX results provide the evidence that Mn is incorporated into the ZnO crystals. A strong and wide ultraviolet emission has been observed for the Mn doped ZnO micro and nanocrystals as evidenced by the photoluminescence spectra at room temperature.PL spectra reveals that as synthesized samples are highly pure and crystalline. Magnetism in these samples was also studied by using vibrating sample magnetometer.