ZnBeMgO thin films based UV Detectors by Spin Coating

Abstract

ABSTRACTBe and Mg co-doped ZnO films Zn1-x-yBexMgyO (0 ≤ x ≤ 0.10, 0 ≤y ≤ 0.20) have been deposited for the first time by novel chemical deposition or spin coating method. From the x-ray diffraction patterns it is noticed that the pristine ZnO film exhibits wurtzite polycrystalline structure, however, co-doped films are (0002) preferentially oriented. The (0002) peak intensity also increases with the corresponding increase in dopants concentrations. The systematic decrease in the c-axis lattice parameter value in the co-doped films as compared to pure ZnO film suggests the incorporation of smaller ions Be+2/Mg+2 at Zn+2 site. From the optical transmittance measurement it is noticed that all the films exhibited almost 80% transmittance in the visible region with sharp and single absorption edges in the UV region. The cut-off wavelength shifts from 375nm for the ZnO film to 330nm with 10 Be and 20% Mg co-doped film. The bandgap calculations revealed an increase in bandgap from 3.26eV (ZnO) to 3.60eV (Zn0.7Be0.1Mg0.2O) film. Such an increase in the co-doped films fabricated by a much simpler and cheaper process is very useful in the realization of UV radiation detection without having little interference from the visible light.