Incorporation of Ga in $ZnO∕GaN$ epitaxial films Available to Purchase

Growth of zinc oxide (ZnO) layers on gallium nitride (GaN) substrates benefits from the small lattice mismatch of these two materials. We report on spatially resolved cathodoluminescence studies of ZnO layers grown by a modified chemical vapor deposition process on GaN templates deposited on sapphire substrates. Line scans across the $ZnO∕GaN$ interface reveal the incorporation of gallium from the template into the ZnO layer. Transmission electron microscopy and micro-Raman measurements both indicate that strain relaxation occurs within a distance of a few nanometers from the $ZnO∕GaN$ interface. The diffusion coefficient of gallium in ZnO is determined.