T V Torchynska
Instituto Politécnico Nacional, México
Title: Emission, structure and aging of silver doped ZnO nanorod films
Biography
Biography: T V Torchynska
Abstract
ZnO has attracted scientific attention during the last decade owing to its potential application in short-wavelength and hightemperature optoelectronics, such as short-wavelength light emitting diodes, photodetectors, ultraviolet lasers, etc. To fabricate the optoelectronics devices n- and p-type ZnO NC layers are required. As in any II-VI semiconductors, the preparation of p-type ZnO NC layers is the difficult task owing to the high concentration of native shallow donors. It was shown recently that Ag is a most promising element from the group IB atoms for p-type ZnO doping. Additionally, Ag-doping stimulates the near band edge (NBE) emission in ZnO NCs that is interesting for optoelectronics. The emission, structure and the aging process have been studied in the silver doped ZnO nanorods (NRs) obtained by ultrasound spray pyrolysis with different Ag concentrations within of 1-4 at%. Electronic scanning microscopy (SEM), X ray diffraction (XRD), photoluminescence (PL)
spectroscopy and its temperature dependences have been applied. It is revealed that at low Ag content (1-2 at%), the doping improves essentially the structure and emission of ZnO Ag NRs. Simultaneously, the inter-planar distances in ZnO NR crystal lattice decreases and the new Ag related PL band with the peak at 2.87-2.95 eV at 10 K appears in PL spectra. At higher Ag content (3-4%) the PL intensity of majority PL bands falls down together with the stimulation of orange PL band intensity, the inter-planar distances in ZnO NR crystal lattice increase and the formation of metallic Ag nanocrystals have been detected by
XRD. The aging process is accompanied by the new Pl band (2.87-2.95 eV) falls down as well and intensity raising the orange PL band. The PL temperature dependence study permits to analyze the nature of defects responsible for the new Ag-related PL band (2.87-2.95 eV) and for the orange PL band. The optimized concentrations for the Ag doping of ZnO NRs have been revealed.