GaN nanocolumnar structures were grown by plasma-assisted molecular beam epitaxy (PAMBE) and also fabricated by electron cyclotron resonance reactive ion etching (ECR-RIE) of a compact GaN film parallel to the  direction of the Si (111) substrates. Scanning electron microscopy shows that the nanocolumns fabricated by PAMBE have a length of about 300–500 nm with diameters ranging from 20 to 150 nm while nanowhiskers formed by RIE have diameters of 40–80 nm and a height between 1.4 and 1.7 µm. A comparative study of the vibrational spectrum (including optical and interface phonons) of the nanostructures using conventional macro-Raman and micro-Raman scattering as well as surface-enhanced Raman scattering is presented.
16 Jun 2006
Volume: 18 Issue: 26 Pages: 5825
Journal of Physics: Condensed Matter