Research On Cu-doped Orag-doped ZnO Nanostructure

ZnO, known as the universal materials, a wide band gap semiconductor with a variety of excellent properties, has a great potential applications in semiconductor pressure sensing device,ultraviolet-green-blue luminescent device and many other respects. It's expected to produce a ZnO photoelectric device with excellent properties, and the physicochemical properties will be changed greatly when the semiconductor is doped. In this paper, using transition-metal element, (Cu, Ag) as doping materials, ZnO micro/nanostructures were synthesized by Chemical Vapor Deposition. The morphologies and crystal structures of the as grown samples were characterized, and the photoluminescence (PL) and Raman scattering properties were measured and discussed. The main contents are as follows:1. Employing two different dopants (Cu and CuI, we call them the first and second way respectively), two kinds of Cu-doped ZnO nanostructures were synthesized. When Cu was used as dopant, the product is ZnO Tetrapods. X-ray diffraction (XRD) pattern showed that the (002)crystalline faces diffraction peak shift to high degree (about 0.09°), indicating that the doping atoms has affected the lattice constant. Energy disperse spectroscopy (EDS) indicated that the atomic percentage of Cu element was 1.39 in the sample. When CuI was used as dopant, the controllable ZnO nanorods arrays were synthesized. We found the near band emission was strongly suppressed. On the other hand, a well structured green emission appeared when the PL spectra were measured at 60K low temperature. It's suggested that this structured emission was related to phonon emission of Cu2+.2. Novel microgrooves and microchains morphology of Ag-doped ZnO were synthesized by using AgNO3 powder as dopants. All the XRD pattern of the as-grown product showed that the (002) peak shifted to low degree, indicating that the Ag has been doped into the lattice. In comparasion with the Raman scattering of pure ZnO, two additional Raman scattering peaks related to the local vibration mode due to doping process were appeared at 275 cm-1 and 643 cm-1 respectively.3. To analyze the effect of dopant content on the optical properties, UV-Vis absorption, room temperature PL spectra and Raman spectra were measured for the product synthesized by changing the contents of AgNO3, . The results showed that, the bandgap of ZnO narrowed because of doping. Near band emission intensity of room temperature PL spectra also decreased and shifted to red, while the visible light emission intensity gradually increased with the increase of AgNO3. Raman scattering frequency shifted toward the low frequency with the increasing of the dopant content linearly. We discussed and explained these phenomena.