Product Code: ICAL09_M1007

Effects of KrF (248_nm) Excimer Laser Irradiation on Structural and Optical Properties of ZnO Single Crystal
Authors:
Jie Liu, BeiJing University of Technology; BeiJing Peoples Republic of China
Yijian Jiang, Beijing University of Technology; Beijing Peoples Republic of China
Presented at ICALEO 2009

The properties of ZnO single crystal irradiated by a pulsed 248nm excimer laser have been systematically studied by AFM, XRD, photoluminescence and Raman measurements. It was observed that the surface roughness and the grain size on the surface of the irradiated ZnO crystals became larger, as well as their band-edge (BE) emissions at room temperature were found to become stronger and shift to higher frequency with increasing laser energy densities, but weaker above 500 mJ/cm-1. Green luminescence emissions had the similar trend. Our Raman results show that bulk properties of the irradiated ZnO crystal diminish but the defect-, surface-related features display as laser energy densities increases. The Raman spectra of the irradiated ZnO crystal are deteriorated bulk spectra with spectroscopic line broadening and merging, line intensity reducing, and position shifting, because the laser irradiation onto the surface of ZnO crystal leads to the thermal decomposition of ZnO into metallic Zn and oxygen gas and the increase of oxygen vacancies or interstitial Zn atoms. A new phonon at 128 cm-1 related to interstitial Zn atoms in the irradiated ZnO crystal was observed. They reflect the effects of laser irradiation on the properties of ZnO.