Mg1-xZnxO thin films were deposited under different pressures during the growth process, which is modulated by different Ar/O-2 flow ratio. When growth pressure increases, the growth orientation of MgZnO thin film changed from (200) to (111) because of the decrease in migration energy of reactive Mg, Zn and O atoms from MgZnO target material. The band gap of MgZnO thin films decreased when growth pressure increased from 2 Pa to 6 Pa, which is reason from more Zn atoms combined with O atoms in (111) orientation MgZnO crystal lattice in MgZnO thin film deposited at higher pressures. But when the growth pressure increased from 6 Pa to 7 Pa, the band gap value of MgZnO thin films increased because less Zn atoms than Mg atoms combined with O atoms in MgZnO crystal lattice at higher pressures with the same (111) orientation. (C) 2014 Elsevier B.V. All rights reserved,