Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 80: GaN: Preparation and Characterization V (mainly Cathodoluminescence)
HL 80.2: Vortrag
Donnerstag, 29. März 2012, 11:30–11:45, ER 270
Growth and optical properties of mask-free and uncatalyzed GaN nanorods by metal-organic vapor phase epitaxy — •Christian Tessarek and Silke Christiansen — Max Planck Institute for the Science of Light, Erlangen, Germany
Nanorod (NR) structures have the potential to significantly reduce the defect density in heteroepitaxially grown GaN. Furthermore, in case of a high density and high aspect ratio the surface to volume ratio is increased in comparison to a two dimensional film.
Our approach is the growth of mask-free and uncatalyzed GaN nanorods by metal-organic vapor phase epitaxy. A simple three step method is utilized consisting of nitridation of the sapphire substrate, deposition of a GaN nucleation layer and finally the growth of GaN NRs. Vertically aligned and hexagonal shaped NR structures were achieved with a density of up to 108 cm−2, diameters in the range from 100 nm to some µm, heights up to 30 µm or aspect ratios of up to 30, depending on the growth parameters.
Optical properties of the GaN NRs were determined using spatially and spectrally resolved room temperature cathodoluminescence. It will be shown that the yellow defect band luminescence can be suppressed while the GaN near band edge emission is increased. Finally, the appearance of whispering gallery modes in regular hexagonal shaped GaN NRs will be presented.