Effects of growth variables on the properties of deep-UV ZnMgAlO thin films lattice matched to ZnO

Effects of growth variables on the optical, structural and electrical properties of magnetron-sputtered Zn0.78Mg0.16Al0.06O films were characterized in detail. It was observed that the energy band gap (∼3.95 eV) and the lattice constant of the films were not critically affected by the growth variables. The quality of the films improved when sputtered at high temperatures in the plasma with high O2 concentration. Films grown from pure oxygen plasma showed high resistivity, 4×104-1×105 Ωcm, whereas films grown in Ar plasma showed much lower resistivity,∼5×10−2 Ωcm. Growth at high temperature resulted in drastic decrease in carrier concentration and increase in the mobility. It was proposed that growth within oxygen environments would lead to high-quality stoichiometric films with low defect concentrations, resulting in highly resistive films.