Pure deep-ultraviolet cathodoluminescence from rocksalt-structured MgZnO grown with carbon-free precursors

Rocksalt-structured MgZnO thin films of optical band gaps as large as about 5.8-6.6 eV were grown on MgO substrates by a mist chemical vapor deposition method using carbon-free precursors. MgZnO thin films with the dislocation density of less than 10(7) cm(-2) were obtained. Pure deep-ultraviolet cathodoluminescence was observed without noticeable emission at the longer wavelengths, being attributed to improved crystallinity as well as reduced carbon impurity. The highest emission energy (the shortest emission wavelength) at the luminescence peak was 6.24 eV (199 nm) at 6 K. (c) 2019 The Japan Society of Applied Physics