A technique for nanopatterning diverse materials János Szívós a,b, ⁎, Miklós Serényi a , Szilárd Pothorszky a , András Deák a , Gábor Vértesy a , György Sáfrán a a Institute for Technical Physics and Materials Science, Centre for Nuclear Research, Hungarian Academy of Sciences, H-1121 Budapest, Konkoly-Thege M. út 29–33, Hungary b Doctoral School of Molecular- and Nanotechnologies, University of Pannonia, H-8200 Veszprém, Egyetem utca 10, Hungary abstract article info Article history: Received 18 August 2016 Revised 17 January 2017 Accepted in revised form 22 January 2017 Available online 23 January 2017 A fast and high throughput technique has been proposed for the preparation of ordered nanopatterns. A self-or- ganized monolayer of silica nanospheres (Langmuir-Blodgett film) is laid on and its hexagonal pattern is trans- ferred to the sample surface by means of RF plasma etching. The technique was developed with the aim to fabricate nanopatterns onto surfaces or thin films of diverse materials. It is a fast, low cost, environmentally sound technique for the fabrication of hexagonal patterns of feature size down to a few ten nanometers. The mechanism and the parameters of RF plasma patterning affecting the nanostructure formation were revealed in sputter deposited Pt layers by means of scanning and transmission electron microscopy techniques. Moreover, the versatility of the proposed method is demonstrated by fabricating hexagonal patterns in samples of various metals, semiconductors, and insulators. © 2017 Elsevier B.V. All rights reserved. Keywords: Nanopatterning Langmuir-Blodgett film RF plasma etching Ordered nanostructures Thin films 1. Introduction Many fields of the leading edge technology (microelectronics and -mechanics, computer industry) are in a constant need of cheap and high-throughput nanoscale fabrication processes. Therefore, high re- search interest is given on the nanoscale modification of various mate- rials. This includes nanopatterning i.e. the preparation of nano-size ordered structures of surfaces and thin films. Nanopatterned metal layers need to be applied in the fields of nanolithography [1], nanoelectromechanical systems (NEMS) [2], energy harvesting [3], semiconductor devices [4] and solar cells [5]. Metal nanostructures can be used as chemical catalysts [6], and even biosensors made with flexible nanopatterned metal electrodes can detect enzymes by modify- ing pattern period and size [7]. Moreover, nanopatterned metal lines serve as barriers to lateral mobility of the supported lipid membrane [8]. The high need to develop bit patterned magnetic recording media (BPM) [9] is one of the main boosts in the progress of the nanopatterning techniques. There are several techniques for the fabrica- tion of ordered nanostructures classified as both top-down (e-beam li- thography [10], nanoimprinting [11], focused ion beam lithography (FIB) [12]) and bottom-up (electron beam induced- or focused ion beam deposition (EBID or FIBD) [13] [14], molecular self-assembly [15]) techniques. Almost all processes mentioned here suffer from high costs and low throughput. A hybrid method, the nanosphere li- thography [16] [17] can be a promising option. The present authors proposed, earlier, a fast and low cost approach for patterning AlO x layers of various microstructures [18]. That comprises a treatment of the sur- face through a monolayer of silica nanoballs (LB film) by means of a pulse of an UV-laser of 30 ns pulse length. A cratering of the oxide occurs due to the absorbed high energy at the focus spots of the individual sil- ica nanosphere lenses. Unfortunately, the absorption mechanism of the laser light is different for metals and insulators [19], that in normal case, paralyze the application for metals; it is likely that an extreme short (femtosecond) pulse UV laser would be necessary [20] for patterning metal surfaces. There are a few techniques that utilize LB film as template for nanopatterning [21,22,23,24]. These actual processes have serious drawbacks compared to the method proposed in this paper. First, the size of the nanospheres of the LB films applied at the existing techniques is typically 5–10 times larger than that of produced and utilized in the present work. Furthermore, the existent processes employ reactive ion etching [25] that requires expensive and harmful gases (e.g. SF 6 or CF 4 ). Last but not least, reactive ion etching is, obviously material selective. The subject of this work is to develop a fast, cheap and high through- put method for the direct fabrication of ordered nanoscale patterns in wide range of materials including metals. The here proposed technique does not involve wet etching so we consider it as environmentally sound. A monolayer of hexagonally self-assembled silica nanospheres prepared by the Langmuir-Blodgett (LB) technique [26,27] is applied as a template for further treatment of the surface. The nanopatterning is realized by RF plasma etching of the samples through the LB film. The RF plasma etching is advantageous because, beside metals and semiconductors, it is applicable for etching insulating materials, as well. Thanks to the fact that both LB films and RF plasma can be applied Surface & Coatings Technology 313 (2017) 115–120 ⁎ Corresponding author at: Institute for Technical Physics and Materials Science, Centre for Nuclear Research, Hungarian Academy of Sciences, H-1121 Budapest, Konkoly-Thege M. út 29–33, Hungary. E-mail address: szivos@mfa.kfki.hu (J. Szívós). http://dx.doi.org/10.1016/j.surfcoat.2017.01.088 0257-8972/© 2017 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Surface & Coatings Technology journal homepage: www.elsevier.com/locate/surfcoat