Study of photoluminescence from annealed bulk-ZnO single crystals
Abstract
We have investigated the influence of rapid thermal annealing on the photoluminescence of bulk-ZnO single crystal. As-grown ZnO wafer, illuminated by 325 nm ultraviolet light at 4.2 K, emitted the visible luminescence of pale green centered of 2.29 eV. The luminescence was observed by the anneal at the temperature range between 400 °C and 1000 °C, however, its intensity decreased with anneal temperature. The free-exciton and the 2.18 eV emission line were obtaiend by the anneal at 1200 °C for 60 sec. From the X-ray diffraction and the surface morphology measurments, the improvement of the crystallinity of bulk-ZnO crystal were confirmed. We suggest that a rapid thermal annealing technique is convenience to improve the the quality of bul-ZnO single crystals. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
