Nano Express

Nanoscale Research Letters

, 3:123

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

A Novel Self-aligned and Maskless Process for Formation of Highly Uniform Arrays of Nanoholes and Nanopillars

  • Wei WuAffiliated withEECS Department, Northwestern University
  • , Dibyendu DeyAffiliated withEECS Department, Northwestern University
  • , Omer G MemisAffiliated withEECS Department, Northwestern University
  • , Alex KatsnelsonAffiliated withEECS Department, Northwestern University
  • , Hooman MohseniAffiliated withEECS Department, Northwestern University Email author 


Fabrication of a large area of periodic structures with deep sub-wavelength features is required in many applications such as solar cells, photonic crystals, and artificial kidneys. We present a low-cost and high-throughput process for realization of 2D arrays of deep sub-wavelength features using a self-assembled monolayer of hexagonally close packed (HCP) silica and polystyrene microspheres. This method utilizes the microspheres as super-lenses to fabricate nanohole and pillar arrays over large areas on conventional positive and negative photoresist, and with a high aspect ratio. The period and diameter of the holes and pillars formed with this technique can be controlled precisely and independently. We demonstrate that the method can produce HCP arrays of hole of sub-250 nm size using a conventional photolithography system with a broadband UV source centered at 400 nm. We also present our 3D FDTD modeling, which shows a good agreement with the experimental results.


Microspheres Lithography Nanoholes Nanopillars