Pulsed metal organic chemical vapor deposition (PMOCVD) was used to grow high Mg
content, high quality, wurtzite MgxZn1-xO (MgZnO)
epitaxial film to realize photodetectors and emitters in the solar blind
spectral window. MgZnO films with various Mg contents were deposited on c-plane
Al2O3 with and without AlN buffer layer. The band gap
of the films range from 3.24 eV to 4.49 eV, corresponding to fraction of Mg
between x=0.0 to x=0.51, as
determined by Rutherford backscattering spectroscopy (RBS). Cathodoluminescence
(CL) measurement showed a linear blue shift in the spectral peak position of
MgxZn1-xO with an increase in x. No
multi-absorption edge or CL band splitting was observed, indicating the phase
purity of the films and was confirmed by XRD analysis. The surface quality of
the films has improved with the increase in Mg content. To the best of our
knowledge, the current result shows the highest Mg content
(x=0.51), high quality, single phase wurtzite MgZnO
epitaxial film ever grown by MOCVD. This is realized due to the non-equilibrium
behavior of PMOCVD in which radicals that are formed during the growth process
will have insufficient time to reach equilibrium.