Growth characteristics of single-crystalline ZnMgO layers by ultrasonic spray assisted mist CVD technique

A simple, safe, and cost‐effective ultrasonic spray assisted mist chemical vapor deposition (CVD) method has been applied for the growth of Zn1−xMgxO alloy thin films on a‐plane sapphire substrates with ZnO buffer layers. Single‐crystalline (0001)‐oriented wurtzite Zn1−xMgxO thin films have been prepared for x of between x = 0 and 0.25. The optical bandgap can be tuned from 3.28 to 3.96 eV with a pure wurtzite phase (x = 0–0.25). At x = 0.31 slight segregation of rocksalt ZnMgO was seen in wurtzite ZnMgO, but the bandgap was as large as 4.10 eV. Zn1−xMgxO alloys exhibited room temperature ultraviolet cathode luminescence (CL) at energies between 3.28 (x = 0) and 4.04 eV (x = 0.31) without no observable deep level emissions. This novel growth technique can contribute to evolution of various oxide thin films of unique functions.