Experimental investigation of cubic to hexagonal ratio for GaN layers deposited on 3C-SiC/Si

We report results of a comparative investigation of GaN layers deposited on 3C-SiC/Si. Checking for the cubic form, neither X-ray nor micro-Raman scat tering experiments could give an unambiguous answer. We show that selective excitation of the low temperature photoluminescence (LTPL) spectrum is a m uch better teal. Indeed, in many cases, a clear cubic signature was resolve d around 3.25 eV (bound exciton feature) which exhibited, from time-resolve d spectroscopy, a reasonably short decay-time of a few hundred picoseconds. From comparison of the corresponding intensity with the pure hexagonal one , we estimated the cubic/hexagonal ratio to range from negligibly small to approximate to 16%.