Nanopendeo coalescence overgrowth of GaN on etched nanorod array

This paper reports the characteristics of gallium nitride layers that have been grown on top of an etched array of nanorods. Nanoimprint lithography has been used to create nanorods on a wafer-scale that are subsequently passivated to allow selective regrowth from their tips by MOVPE. The first epitaxial growth step favoured lateral growth and the second resulted in a planar coalesced layer of gallium nitride. It was found that smooth planarised overgrowth required careful timing of the growth transition between the two steps and that the crystallographic quality of the overgrown layer was very sensitive to the nanorod template properties, in particular the amount of unpassivated nanorod surface.