| Popis: |
We have attempted the growth of GaN by RF-MBE which crystalline quality is a match for that by MOCVD, performing homoepitaxial growth using MOCVD-GaN as a substrate. We confirmed that homoepitaxial GaN had Ga polarity by (1 x 1) RHEED streaky pattern after cooling down. 10 min-BHF-etching was the most effective for cleaning the surface of GaN substrate, and as the result crystalline quality of homoepitaxial GaN was improved. Thermal annealing of GaN substrate was also affect for the improvement of crystalline quality of homoepitaxial GaN. From XRD measurement, FWHM of diffraction spectrum from homoepitaxial GaN almost equaled to that from GaN substrate. So, the crystalline quality of homoepitaxial GaN was not inferior to that of GaN substrate. Large compressive strain in c plane of homoepitaxial GaN indicated that homoepitaxy prevented 3D growth and/or formation of defects. From PL measurement, we observed radiative recombination of free excitons clearly from homoepitaxial GaN. |
