Growth of InN nanorods on glass substrates by molecular beam heteroepitaxy

Vertically aligned InN nanorods with uniform diameter and length were selectively grown on AlN/glass templates by plasma-assisted molecular beam epitaxy. The high-crystal-quality InN nanorods grow preferentially in the [0002] direction. On a macroscopic scale, the nanorods are found to be entirely relaxed, but possess non-negligible microscopic strain. Judging from the Raman and photoluminescence (PL) spectra, it can be inferred that the strain and/or surface electron accumulation effects may be the likely factors causing the PL shift, rather than the quantum size effect. The calculated conduction band offsets of the InN/AlN nanorod heterojunction along and perpendicular to the c-axis were 4.12 ± 0.1 and 4.11 ± 0.1 eV, respectively. These large offsets provide an alternative way of obtaining rectifying behavior in n-n InN/AlN heterojunctions with nanorod architectures.