ZnO nanostructures were grown on Au-coated Si (100) substrates by carbonthermal reduction method with the help of Ar at the beginning of growth. The structural and optical properties of ZnO nanostructures strongly depended on the supply time of Ar. When the given time of Ar gas current was 90s, sample was ZnO nanowires with hexagonal morphology. The Raman spectroscopy revealed the low level of oxygen vacancies and Zn interstitials in samples. Room temperature photoluminescence (PL) spectra exhibited the intensity of green emission increased on the condition of rich oxygen (decrease given time of Ar) and the nanowire had strongest intensity of UV emission compared with other nanostructures. Green emission is ascribed to the electron transition from the bottom of the conduction band to the antisite defect O Zn level.
We prepared Co-doped ZnO films by the electrochemical deposition. X-ray diffraction (XRD), high resolution transmission microscopy (HRTEM), x-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM), x-ray absorption near-edge structure (XANES), vibrating sample magnetometer (VSM), optical absorption, and photoluminescence (PL) measurements were carried out on the samples. The results showed Co atoms substituted Zn atoms in the ZnO lattice without the formation of the impurity phase. VSM measurements showed the ferromagnetic properties for the Co-doped ZnO samples. When the Co doping concentration increased, the band gaps were widened and the PL peak positions shifted towards the short wavelength direction.
Mn-doped ZnO were synthesized by solid state reaction and sol-gel method respectively. It was found that samples synthesized by solid state reaction containing Mn 2 O 3 and MnO 2 are a mixture of ferromagnetic and paramagnetic phases. Contrary, samples without second phases were found to be paramagnetic at room temperature. According to previous report, interface effects between Zn-rich Mn 2 O 3 and MnO 2 interfaces may be the origin of the ferromagnetic behavior observed in our samples prepared by solid reaction, so the alloy of Zn 1−x Mn x O may be paramagnetic at room temperature. Prepared by sol-gel technique, the samples without second phases in the XRD patterns are also room-temperature paramagnetic. Therefore we believe that the magnetism of Zn 1−x Mn x O is paramagnetic at room temperature.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.