Preparation of large area sub-50 nm polymer nanoring arrays

We have prepared large area (4 mm2) periodic arrays of polymer nanorings on GaAs and Si by means of an electron-beam lithography process based on dose-dependent negative PMMA. The rings have identical outer diameters which can be precisely chosen between 40 and 95 nm. The width of the inner diameter can be adjusted between 20 and 60 nm, resulting in line widths between 10 and 20 nm. The periodicity of the rings can be arbitrarily chosen down to 500 nm. The nanorings have been characterized by using several high resolution microscopy techniques including high resolution scanning electron microscopy (HR-SEM) and atomic force microscopy (AFM). First experiments to prepare lattices of metal nanorings have been performed by using the nanorings as a negative resist.