High quality ZnO film formation by CO2laser annealing of buried films in SiO2matrix

We have proposed the ZnO film annealing method using CO2 laser. We fabricated the layered structure to enhance the annealing effect. The sample structure was SiO2/ZnO/Quartz substrate. The ZnO film was deposited on quartz by a pulsed laser deposition and the SiO2 film was deposited on ZnO film by physical vapor deposition. We used photoluminescence measurement to investigate the optical property of ZnO film. We found that the optical property was improved in two steps. The first step was surface passivation effect of SiO2 coating and the second one was the annealing effect of CO2 laser. We analyzed the fabricated film for surface state by XPS and for crystallinity by TEM measurements. The change of ZnO surface state was observed when the SiO2 film was deposited on the ZnO film. The change of crystallinity of ZnO was observed after CO2 laser annealing. The crystallinity of ZnO before laser annealing seemed to be polycrystal, while the crystallinity of ZnO after laser annealing seemed to be single crystal.