Effect of annealing on the photoluminescence characteristics of solution grown ZnO nanorods array
Presented by Mr. Crispin MBULANGA on 8 Jul 2014 from 10:00 to 10:20
Type: Oral Presentation
Track: Track C - Photonics
Abstract The effect of annealing in oxygen and nitrogen on the luminescent properties of ZnO nanorods grown by Chemical Bath Deposition (CBD) has been studied. Special emphasis was given to the visible part of the spectrum. X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) analysis reveal that the as-grown nanorods are well aligned, have good crystalline quality and are orientated along the c-axis. The photoluminescence (PL) spectra of the as-grown ZnO nanorods show strong near band edge (NBE) excitonic emission and weak visible deep-level emission (DLE), which indicate good optical properties and very few structural defects. However, after a sequential annealing of the nanorods in oxygen and nitrogen, the PL spectra reveal DLE that extends into the near infrared (out to ~950 nm). The analysed XRD spectrum shows only the  reflection, which indicates a preferred orientation of the nanorods with the c-axis perpendicular to the substrate. The SEM image confirms this. Based on annealing studies in different environments and annealing temperatures (from 200 to 800 <sup><o>C), three possible DLE transition lines are deduced. More details on the effects of annealing on the photoluminescence characteristics of solution grown ZnO nanorod arrays on the DLE will be discussed.
Prof J. R. Botha, Reinhardt.Botha@nmmu.ac.za, Nelson Mandela Metropolitan University