Synthesis and optical properties of InN nanowires and nanotubes

InN nanowires and faceted hexagonal InN nanotubes are synthesized by catalyst-free chemical vapor deposition at different temperatures. Both have the single crystalline wurtzite structure and grow along the c axis. Different growth dynamics are suggested for the difference in morphology. Observations of phonon-plasmon coupled modes in their Raman scattering suggest of high electron concentrations. Absorption edges in their optical spectra have energies slightly higher than 1 eV, showing blueshifts from the fundamental band gap of ∼0.7 eV, recently observed in epitaxial films. The shifts are argued to be the result of the Burstein-Moss effect.