Chemical vapor deposited diamond films grown on strained gallium nitride-coated quartz
substrate are found to display a dominantly hexagonal diamond phase. The phase
identification is done using Raman spectroscopy and orientation imaging microscopy (OIM).
The presence of a 1324.4 cm− 1 band in the Raman spectra is attributed to a hexagonal
diamond symmetry, but the unambiguous signature of the hexagonal phase is confirmed by
OIM. A phase map of the sample clearly shows that 88% of the scanned sample area is …