Epitaxial growth of INN nanorods on nitridated chromium nanoislands under the in-rich regime

Vertically aligned inverted-cone-like InN nanorods were epitaxially grown on Si(III) substrate by molecular beam epitaxy (MBE) using AlN buffers and nitridated chromium (NC) nanoislands under In-rich environment. The Al droplets were limited to between NC nanoislands so that the lateral diffusion was suppressed. The spot-like AlN nuclei aided the subsequent growth of InN nanorods more uniform and well aligned. X-ray diffraction (XRD) of InN nanorods exhibits a hexagonal phase and (0002) oriented growth. The structural analysis performed by Raman scattering indicates that InN nanorods are wurtzite-type InN crystals with low structural disorders and defects, which contain low concentrations of electrons. The photoelectron spectra depict the considerably reduced surface states and In-In bonds of InN nanorods, while the valence band spectra reveal the presence of surface band bending in InN nanorods. The InN nanorods are free from charge trapping effects due to Fermi-level pinning, which may deplete the carriers.