GaN nanocolumns formed by inductively coupled plasmas etching

GaN nanocolumns were formed by inductively coupled plasma (ICP) etching. It was found that tops of these nanocolumns were hexagonal with the c-axis perpendicular to substrate surface. It was also found that density of the GaN nanocolumns depends strongly on etching parameters which suggests that the formation of these GaN nanocolumns was not related to the dislocation density in the original GaN epitaxial layers. Furthermore, it was found that we can reduce the dimension and increase the density of the GaN nanocolumns by decreasing the bias power during ICP etching.