ABSTRACTVarious shaped single-crystalline gallium nitride (GaN) nanostructures were produced by chemical vapor deposition method in the temperature range of 900–1200 °C. Scanning electron microscopy, transmission electron microscopy, electron diffraction, x-ray diffraction, electron energy loss spectroscopy, Raman spectroscopy, and photoluminescence were used to investigate the structural and optical properties of the GaN nanostructures. We controlled the GaN nanostructures by the catalyst and temperature. The cylindrical and triangular shaped nanowires were synthesized using iron and gold nanoparticles as catalysts, respectively, in the temperature range of 900 – 1000 °C. We synthesized the nanobelts, nanosaws, and porous nanowires using gallium source/ boron oxide mixture. When the temperature of source was 1100 °C, the nanobelts having a triangle tip were grown. At the temperature higher up to 1200 °C the nanosaws and porous nanowires were formed with a large scale. The cylindrical nanowires have random growth direction, while the triangular nanowires have uniform growth direction [010]. The growth direction of the nanobelts is perpendicular to the [010]. Interestingly, the nanosaws and porous nanowires exhibit the same growth direction [011]. The shift of Raman, XRD, and PL bands from those of bulk was correlated with the strains of the GaN nanostructures.
Preparation of large-scale digitization samples for automated electron microscopy of tissue and cell ultrastructure
