Effect of annealing atmospheres on photo-luminescence property of ZnO nano-thin films

Zinc oxide nano-thin films were prepared on Si(1 0 0) substrate by a sol–gel method and dip-coating technique with Zn(Ac)2·2H2O as the raw material. The thin films treated in different annealing atmospheres (air, H2, N2) were characterized by TG, XRD and AFM techniques and their photoluminescence properties were also investigated. The results indicated that the annealing atmospheres influenced the particle sizes of ZnO. The particle size was smaller if the film treated in air while that was bigger if the film treated in H2. In further, they played an important role on the photoluminescence properties of ZnO films. The blue light emission was obviously increased if the films treated in N2, while the ultraviolet (UV) emission was improved greatly if the film treated in H2. Compared with ZnO films treated in N2 and H2 gases, the intensities of UV and red emission resulted from the films treated in air were much weaker.

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► The annealing atmospheres influenced the particle size and the PL properties of ZnO.
► The blue light emission was obviously increased when the films were treated in N2.
► The ultraviolet emission was greatly improved after the films were treated in H2.