9-13 July 2012
MOCVD grown ZnO on R-sapphire: effect of high growth temperature and high VI/II ratio on the morphology and optical properties
Presented by Dr. Kharouna TALLA on 10 Jul 2012 from 17:30 to 19:30
Type: Poster Presentation
Session: Poster Session
Track: Track A - Division for Condensed Matter Physics and Materials
ZnO thin films were deposited on R-sapphire substrate by metal organic chemical vapour deposition. The effect of high growth temperature on the surface morphology and optical properties is investigated. The influence of VI/II ratio is also considered. The optical and structural properties of films grown on R-sapphire are also compared with those of films grown on C-sapphire. Using high resolution electron microscopy, the interface was examined and the formation of stacking faults and dislocation inspected. Scanning electron microscopy and photoluminescence spectroscopy were used to characterize the morphological and optical properties, respectively. High growth temperature (~ 750 oC) clearly improves the luminescence of the ZnO films, while reducing the structural defects. High VI/II ratios (~ 900) produce deep level emission. Smooth and dense films are seen on R-sapphire substrate while columnar (rod-like) structures dominate on the C-sapphire.
J. R. Botha, firstname.lastname@example.org, NMMU