Fabrication of an inorganic nano structure for a large area via electrohydrodynamic lithography (EHL)

Electrohydrodynamic lithography (EHL) is one of several unusual lithographic techniques for fabricating sub-micrometer structures over a large area. EHL uses the electrohydrodynamic (EHD) film instability induced by a laterally modulated electric field, which allows it to fabricate not only general organic structures but also structures of various components, such as diblock copolymers and inorganic materials, without contact between the resist and the stamp. Furthermore, EHL is a very special lithographic technique in that diverse structures are fabricated from one stamp via electric field modulation. The electric field is controlled by the replication time, air layer thickness, etc. A replicated inorganic structure was demonstrated from a hexagonal hole and line arrays. The heat treatment of the replicated pattern was carried out to obtain the crystalline phase, after which the samples were characterized via Raman spectroscopy. These values were ascertained using field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The results will be useful in providing a facile route for patterning functional metal oxides over a large area. Such a technique can be used to produce photovoltaic cells, memory devices, display devices, etc.