ZnO and MgZnO nanocrystalline flexible films: optical and material properties

An emerging material for flexible UV applications is MgxZn1-xO which is capable of tunable bandgap and luminescence in the UV range of ∼3.4 eV-7.4 eV depending on the composition x. Studies on the optical and material characteristics of ZnO and Mg0.3Zn0.7O nanocrystalline flexible films are presented. The analysis indicates that the ZnO and Mg0.3Zn0.7O have bandgaps of 3.34 eV and 4.02 eV, respectively. The photoluminescence (PL) of the ZnO film was found to exhibit a structural defect-related emission at ∼3.316 eV inherent to the nanocrystalline morphology. The PL of the Mg0.3Zn0.7O film exhibits two broad peaks at 3.38 eV and at 3.95 eV that are discussed in terms of the solubility limit of the ZnO-MgO alloy system. Additionally, external deformation of the film did not have a significant impact on its properties as indicated by the Raman LO-mode behavior, making these films attractive for UV flexible applications.