ABSTRACT

Abstract. Thick GaN films are grown on various templates on c-sapphire substrates, which include molecular beam epitaxy (MBE)-grown low temperature (LT) GaN, MBE-grown LT CrN, high temperature (HT) GaN/CrN buffer layer and metal organic chemical vapour deposition (MOCVD)-grown GaN, using hydride vapour phase epitaxy (HVPE). In order to compare the quality of HVPE-grown thick GaN, samples are characterized using XRD, PL, and SEM for evaluation of crystallinity, optical property and surface morphology. The HVPE-grown thick GaN on GaN/CrN buffer have no cracks at 40 /i m film thickness and FWHM of (0002) co-scan is 497 arcsec. These results indicate the feasibility of a CrN buffer applied to free standing (FS) GaN substrates.