Development of controlled nanosphere lithography technology

Abstract

This work is devoted to the development of nanosphere lithography (NSL) technology, which is a low-cost and efficient method to form nanostructures for nanoelectronics, as well as optoelectronic, plasmonic and photovoltaic applications. Creating a nanosphere mask by spin-coating is a promising, but not sufficiently studied method, requiring a large experimental base for different sizes of nanospheres. So, in this work, we investigated the influence of the technological parameters of NSL by spin-coating on the substrate coverage area by a monolayer of nanospheres with a diameter of 300 nm. It was found that the coverage area increases with decreasing spin speed and time, isopropyl and propylene glycol content, and with increasing the content of nanospheres in solution. Moreover, the process of controllably reducing the size of nanospheres in inductively coupled oxygen plasma was studied in detail. It was determined that increasing the oxygen flow rate from 9 to 15 sccm does not change the polystyrene etching rate, whereas changing the high-frequency power from 250 to 500 W increases the etching rate and allows us to control the decreasing diameter with high accuracy. Based on the experimental data, the optimal technological parameters of NSL were selected and the nanosphere mask on Si substrate was created with coverage area of 97.8% and process reproducibility of 98.6%. Subsequently reducing the nanosphere diameter lets us obtain nanoneedles of various sizes, which can be used in field emission cathodes. In this work, the reduction of nanosphere size, silicon etching, and removal of polystyrene residues occurred in unified continuous process of plasma etching without sample unloading to atmosphere.

Reconfigurable Metamaterial Antenna based an Electromagnetic Ground Plane Defects for Modern Wireless Communication Devices

“…The proposed antenna is fabricated as seen in Fig. 8(a) using Nano sphere lithography and wet chemical etching processes that were used in [25]. The antenna structure is mounted on the Roger substrate to realize low dielectric material loss.…”

Simple and Rapid Monolayer Self-Assembly of Nanoparticles at the Air/Water Interface

“…Natural lithography techniques have various benefits, such as the capacity to create ordered arrays, affordability, cost-efficiency, and compatibility with other lithography techniques. − Nanosphere lithography is a form of natural lithography that employs colloidal nanospheres. This approach produces structures with a variety of applications, including photovoltaics, photocatalysis, and membranes for wastewater purification, as well as plasmonics for biosensing, surface-enhanced Raman scattering (SERS), plasmon-enhanced fluorescence, and solar water splitting. − …”

Spin Coating of Silica Nanocolloids on Mica: Self-Assembly of Two-Dimensional Colloid Crystal Structures and Thin Films

“…Although these processes are suitable for laboratory-scale production, they are less useful for industrial processes due to the time scales and tedious fabrication processes involved. Past studies have demonstrated that the spin-coating process provides a simple and efficient method for the dispersion of small particles onto a substrate [16,17,[45][46][47][48][49][50][51][52][53].…”

“…Lan et al [46] synthesised silica nanocolloids of 196 nm diameter (standard deviation of ±40 nm) and fabricated close-packed colloidal monolayers that have shown promising properties for photonic and plasmonic nanostructures. More recently, Osipov et al [45] employed spin coating and 300 nm PS colloidal particles on silicon substrates to fabricate a high-quality and coverage monolayer close-packed colloidal coating, which was used as a colloidal mask to produce nanoneedles by plasma etching.…”