Undoped and Mg-doped ZnO thin films were deposited on
Si(1 0 0) and quartz substrates using the sol–gel process. The XRD
patterns indicate that the ZnO, ZnO:Mg-2%, ZnO:Mg-4% thin films
possess a polycrystalline ZnO with the hexagonal wurtzite struc-
ture. While the ZnO:Mg-2% and ZnO:Mg-4% thin films exhibit
preferential c-axis orientation. As Mg:Zn atomic ratio is 0.08,
Mg segregates in the form of MgO. AFM analysis revealed that
rms roughness of ZnO thin films increases with increasing Mg concentrations annealed at 873 K. Transmittance of the thin films
is over 85% in the visible region. The optical band gap increases
from 3.26 eV to 3.34 eV with increasing Mg concentration. PL spec-
tra were investigated at room temperature. We can observe the
strong ultraviolet (384–402 nm) emission and the weak blue emis-
sion (∼460 nm) peaks. The ultraviolet emission peaks blueshifts
with increasing Mg doping concentration. On the other hand, the
resistivities of the ZnO films are enhanced by Mg introduction
and increase with increasing doping concentrations. These may
be caused by the lattice distortion in the films and the electrical
barriers by the Mg deposited at the grain boundaries.