This study investigates the crystalline quality, surface, and optical properties of semi-polar GaN (11 2 2) grown on m-sapphire substrates with and without a CrN interlayer using molecular beam epitaxy (MBE). The results of the characterization performed by an X-ray diffraction system, scanning electron microscopy and photoluminescence system, all indicate that the crystalline quality, threading dislocation, surface morphology and optical properties of (11 22) GaN grown with the CrN were superior to those when CrN was not inserted. Details of defect-related emissions of these two samples were observed and investigated in temperature dependent PL measurements, with a low temperature PL spectrum. A weak basal stacking fault related (BSF-related) emission at 3.432 eV was observed in these two samples. In comparison, the BSF-related emission peak as a shoulder to the near band edge (NBE) peaks for the semi-polar GaN grown without CrN was hardly distinguishable at a low temperature.

The authors report the influence of CrN nanoisland inserted on growth of baseball-bat InN nanorods by plasma-assisted molecular beam epitaxy under In-rich conditions. By inserting CrN nanoislands between AlN nucleation layer and the Si (111) substrate, it was found that we could reduce strain form Si by inserting CrN nanoisland, FWHM of the x-ray rocking curve measured from InN nanorods from 3,299 reduced to 2,115 arcsec. It is due to the larger strain from lattice miss-match of the film-like InN structure; however, the strain from lattice miss-match was obvious reduced owing to CrN nanoisland inserted. The TEM images confirmed the CrN structures and In droplets dissociation from InN, by these results, we can speculate the growth mechanism of baseball-bat-like InN nanorods.

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