Review of pendeo-epitaxial growth and characterization of thin films of GaN and AlGaN alloys on 6H-SiC(0001) and Si(111) substrates

Discrete and coalesced monocrystalline GaN and Al x Ga 1-x N layers grown via pendeo-epitaxy (PE) originated from side walls of GaN seed stripes with and without SiN x top masks have been grown via organometallic vapor phase deposition on GaN/AlN/6H-SiC(0001) and GaN(0001)/AlN(0001)/ 3C-SiC(111)/Si(111) substrates. Scanning and transmission electron microscopies were used to evaluate the external microstructures and the distribution of dislocations, respectively. The dislocation density in the laterally grown sidewall regions and in the regions grown over the SiN x masks was reduced by at least five orders of magnitude relative to the initial GaN seed layers. Tilting of 0.2 ° in the coalesced GaN epilayers grown over the SiN x masks was determined via X-ray and selected area diffraction; however, tilting was not observed in the material suspended above the SiC substrate and that grown on unmasked stripes. A strong, low-temperature photoluminescence band-edge peak at ~3.45 eV with a FWHM of <300 µ eV was determined on the overgrowth material grown on the