Epitaxy Competence Center

Braunschweig, Germany

Epitaxy Competence Center

Braunschweig, Germany

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Hartmann J.,Epitaxy Competence Center | Hartmann J.,TU Braunschweig | Wang X.,TU Braunschweig | Wang X.,OSRAM | And 17 more authors.
Physica Status Solidi (A) Applications and Materials Science | Year: 2015

The three-dimensional growth of GaN structures as a basis for the fabrication of 3D GaN core-shell LEDs has attracted substantial attention in the past few years. GaN nanorods or microrods with high aspect ratios can be grown by selective area epitaxy on a GaN buffer through a SiOx mask. It has been found earlier that silane substantially initiates vertical growth, with the exact underlying mechanisms being still unclear. Here, the influence of silane on the 3D GaN column growth was investigated by performing detailed growth experiments in combination with a thorough surface analysis in order to get insight into these mechanisms. The vertical growth rate is significantly enhanced by high silane fluxes, whereas the saturation of growth rate with the time is reduced. Thus, homogenous GaN columns with an aspect ratio of more than 35 could be achieved. A thin Si-rich layer on the non-polar m-plane facets of the columns has been detected using a combination of transmission electron microscopy, energy dispersive X-ray spectroscopy and Auger electron spectroscopy. This layer is suggested to be the reason for the increase in growth rate, modifying the effective collection range of the species along the sidewalls, and preventing the lateral growth. © 2015 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim.


Waag A.,TU Braunschweig | Waag A.,Epitaxy Competence Center | Waag A.,Laboratory of Emerging Nanometrology | Hartmann J.,TU Braunschweig | And 19 more authors.
2016 IEEE Photonics Society Summer Topical Meeting Series, SUM 2016 | Year: 2016

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. © 2016 IEEE.

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