Characterization of Mg_xZn_{1 - X}O thin films grown on sapphire substrates by metalorganic chemical vapor deposition

Wurtzite-structure Mg_xZn_{1 - x}O materials with five different compositions of x from 0 to 0.14 were grown on sapphire substrates by metalorganic chemical vapor deposition. It was found that increasing Mg content in the Mg_xZn_{1 - x}O not only increased the band gap energy of the film but was also beneficial to the epitaxial growth of p-type Mg _xZn_{1 - x}O without using any doping sources. In addition, the combined ultraviolet photoluminescence (PL) and Raman scattering spectra were measured with PL-Raman signals obtained together, showing a blue-shift of PL band and variation of resonant Raman multi-order longitudinal optical phonon modes with an increase of Mg content.