AVS 52nd International Symposium
    Nanometer-Scale Science and Technology Tuesday Sessions
       Session NS-TuP

Paper NS-TuP30
Single-Crystal GaN Nanorod Arrays Grown by UHV RF-MOMBE

Tuesday, November 1, 2005, 4:00 pm, Room Exhibit Hall C&D

Session: Nanometer Scale Science and Technology Poster Session
Presenter: C.N. Hsiao, National Applied Research Laboratories, Taiwan
Authors: C.N. Hsiao, National Applied Research Laboratories, Taiwan
C.-C. Kei, National Applied Research Laboratories, Taiwan
C.K. Chao, National Central University, Taiwan
S.-Y. Kuo, National Applied Research Laboratories, Taiwan
Correspondent: Click to Email
Well-aligned GaN nanorod arrays have been grown by ultra-high vacuum metal organic molecular beam epitaxy using RF radical nitrogen (RF-MOMBE) on c-sapphire substrates without any catalyst. The corresponding microstructure and growth kinetics of rods were investigated by in-situ reflection high-energy electron diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, x-ray diffraction, micro-Raman spectroscopy, photoluminescence and high resolution transmission electron microscopy (HRTEM). It was found that the length and diameter of nanorods varies with the growth temperatures, and the rod number density can reach around 10@super 10@ cm@super -2@. HRTEM and corresponding diffraction patterns have revealed the GaN nanorods have a dislocation free, single-crystal hexagonal wurtzite structure with preferential (0001) orientation. However, the selected area electron diffraction patterns (SADPs) for the interface were not clear enough to identify corresponding orientation relationship between rod and substrate. Further research about growth mechanism is still needed in this area. The findings in this work show that the size and density of the rods can be controlled by adjusting the III/V ratio, RF plasma power and growth temperature. In contrast to previous works, the process requires neither catalyst nor the effect of nanometer-sized confinement such as carbon nanotubes. Thus, the single-crystal and dislocation-free GaN nanorods arrays might be useful for practical applications in nanoscale optoelectronic and electronic devices.