Zinc oxide (ZnO), a wide band gap (3.37 eV) and a large exci-
tion binding energy of 60 meV semiconductor, has attracted much
attention for possible applications in optoelectronic devices [1–3].
Zinc oxide (ZnO) has been successfully included in the photonics,
optoelectronics, spintronics, and gas sensors applications [4–6].