Effect Of Carrier Gases On Growth Of Thick Gan Films By Hydride Vapour Phase Epitaxy

The effect of carrier gas on thick GaN film grown by hydride vapour phase epitaxy on (0001) sapphire substrate has been studied by double crystal X-ray diffraction (DCXRD), field emission scanning electron microscope (FE-SEM), photoluminescence (PL) and Hall tester. H-2, as carrier, is propitious to two-dimension growth pattern of GaN film, but it causes production of more defects and impurities. Red shift of band edge emission of PL and a wider FWHM (full wave at half maximum) of DCXRD appear under H-2 atmosphere. N-2, as carrier, reduces the content of defects and impurities. However, the growth interface of GaN forms easily crystallographic facets but not epitaxial (0002) plane, which leads to appearing of embossed surface. It may gain high-quality HVPE-GaN that H-2 and N-2 are adopted as carrier gas sequentially.