Growing GaN nanostructures on graphene

01.01.2016, 00:00

Newsletter 9

GaN and its In- or Al-alloys, all direct bandgap semiconductors, are ideally suited for a wide range of opto-electronic applications. It has been shown that not only layer stacks but also three-dimensional (3D) architectures of micro- and nanorods can be grown and outperform their 2D counterparts, showing faster growth rates and fewer lattice defects. For integration into an optoelectronic device a top and bottom contact is required. The insulating sapphire substrate prevents simple back-contacting of rods so that complex, yield and performance-hampering schemes must be used. As a possible workaround, we transferred graphene (a good electrical conductor) on to the insulating sapphire prior to GaN rod formation. In a recent publication we report on the use of this technique in solid-state-lighting (SSL). Correlated
Raman measurements and scanning electron microscopy imaging reveal that the GaN rods grow on defective graphene where GaN rods can nucleate at dangling bonds. Using a nanoprobe it was possible to demonstrate conductivity between the as-grown GaN rods and the graphene back contact. This study has implications on further developments in the SSL markets.

Contact: martin.heilmann(at)mpl.mpg(dot)demartin.heilmann(at)mpl.mpg(dot)de
Group: Christiansen Research Group
Reference:  M. Heilmann et al., Crystal Growth & Design, 15, 2079–2086 (2015).