Daniel Bichler

Recent developments of 3D GaN core shell architectures towards solid state lighting

Summary form only given. GaN nanorods and related high aspect ratio 3D GaN nanostructures recently attracted a lot of attention since they are expected to be an exciting new route towards extending the freedom for device design in GaN technology. Such structures offer large surfaces, defect free high quality material, as well as non-polar surface orientations, including the possibility to use very large area foreign substrates without implementing large area strain. All of these aspects are difficult or impossible to achieve when planar substrate approaches are used. Meanwhile, such 3D high aspect ratio GaN based nanostructures can reproducibly be fabricated with high aspect ratios and good homogeneity, and more and more device and application aspects are under investigation.Details on the MOCVD growth of such high aspect ratio structures will be given, and the influence of growth parameters (and particularly the silicon doping) on the properties of the quantum wells will be discussed. Silicon is shown to lead to passivation effects at m-plane sidewall surfaces, which hinder the high quality growth of InGaN quantum wells. Strategies to circumvent this problem will be discussed, leading to InGaN quantum wells with PL-IQE values of 60% at room temperature. This talk will give an overview on the state of the art of our 3D GaN research, pointing out the necessity for further epitaxy related research, but also describing the increasingly interesting demonstration of 3D devices and their substantial potential for solid state lighting.