六方相氮化镓微金字塔纳米线共生结构的大量合成和光学特征

he free-standing, hexagonal GaN micropyramid/nanowire homostructures have been successfully synthesized in a large scale by a facile carbon-assisted thermal reduction route. The product was investigated using SEM, XRD, TEM, EDS, SAED, Raman and PL. The pyramids have lengths of 5~8 μm, and the maximal lateral size of 2~3μm, exhibiting the growth characteristic of hexagonal crystal along c-axis. A single nanowire is grown out from the end tip of the pyramid along <0001> growth direction, indicating its epitaxial relationship with the pyramid. Raman studies reveal the characteristics of the hexagonal structure and high-crystallinity of the product. The room temperature PL spectrum displays strong band-edge emission centered at 372nm. The slight redshift originates from N vacancies caused by Ga-rich growth conditions. The formation mechanism was also discussed. The unique micro/nano structures are good entities for the investigation of fundamental physical phenomenon and also as building blocks for functional nanodevices.