Pre-treatment of GaN substrate in Homoepitaxial growth by RF-MBE

The heterointerface between sapphire and GaN is one of serious problems in the growth of GaN by MBE. To overcome this problem, we have performed homoepitaxial growth of GaN by RF-MBE. As a result, homoepitaxial GaN had the equivalent crystalline-quality of GaN substrate from X-ray diffraction measurement. Furthemore, an emission line of radiative recombination of free excitons from homoepitaxial was observed GaN in low temperature PL measurement. We concluded that the growth of high quality GaN film was achieved by homoepitaxial growth. We also studied the effect of surface pre-treatment of GaN substrate. As a result, we observed the increase of PL intensity of excitonic emission line from GaN with BHF etching, which was considered to be due to removal of the oxide on GaN substrate by BHF etching.

RF-MBE

GaN

homoepitaxial growth

radiative recombination of free excitons

surface pre-treatment

removal of the oxide