High-quality GaN epilayer grown by newly designed horizontal counter-flow MOCVD reactor

We have fabricated a newly designed horizontal counter-flow reactor for growing high-quality III-V nitrides and characterized the GaN/sapphire(0 0 0 1) grown in it. The surface morphology of the film was featureless and smooth without any defects such as hillocks or truncated hexagonals. The measured background concentration and carrier mobility of the film 1.5 m thick are 4 x 10(17)/cm(3) and 180 cm(2)/V s, respectively. The defect density measured by TEM is about 1 x 10(9)/cm(2) and the FWHM of DCX-ray curving is 336 arcsec, respectively. This crystallinity is similar to what was commonly obtained for GaN on sapphire until recently. The FWHM of the band-edge emission peak measured by PL at room temperature is typically around 14 and 4 meV for the main extonic peak(DBE) at 10 K. Except DBE at 3.490 eV, two minor structures are detected on the high-energy and low-energy shoulder of DBE at 3.498 eV(FE) and 3.483(ABE).