Optical properties of bulk‐like GaN nanorods grown on Si(111) substrates by rf‐plasma assisted molecular beam epitaxy

Abstract

We have investigated the optical properties of bulk‐like GaN nanorods by cathodoluminescence measurements at room temperature. The bulk‐like nanorods were grown on a Si (111) substrate by rf‐plasma assisted molecular beam epitaxy and are characterized be being surrounded by a compact region. A weak and broad emission line near 3.36 eV was observed at an accelerating voltage of 5 kV. This emission occurs at a lower energy than the emission from unstrained GaN nanorods that protrude from the compact region. Upon increasing the electron beam energy, and hence investigating regions deeper in the sample, the peak emission energy redshifts due to the strain at the substrate interface. The behaviour of the emission line is further investigated with cathodoluminescence measurement on single nanorod's (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)