Epitaxial growth of cubic gan on (111) GaAs by metalorganic chemical vapor deposition

We are reporting the first comprehensive investigation of the structural properties of cubic GaN grown on (111) GaAs substrates by low-pressure metalorganic chemical vapor deposition. The minimum full width at half maximum (FWHM) of the x-ray diffraction (XRD) peak of (111) GaN was found to be ∼12 min. The use of low temperature GaN buffers helps to reduce the FWHM of the XRD. Cross-sectional transmission electron microscopy (XTEM) revealed the presence of columnar structures in the GaN film with widths of the order of 500A. Selected area electron diffraction (SAD) patterns at the interface confirmed that cubic (111) GaN was grown in-plane with the (111) GaAs substrate. Highresolution transmission electron microscopy (HRTEM) showed that the interface characteristics of GaN on (111)A GaAs substrate were better than those of the GaN on (lll)B GaAs substrate.