Dewetting Metal Nanofilms—Effect of Substrate on Refractive Index Sensitivity of Nanoplasmonic Gold
Nanotechnology and Integrated Bioengineering Centre (NIBEC), School of Engineering, Ulster University, Shore Road, Jordanstown BT37 0QB, Northern Ireland, UK
Seagate Technology LLC, 7801 Computer Ave, Bloomington, MN 55435, USA
Energy Efficiency Materials Center, Korea Institute of Ceramic Engineering and Technology, 101 Soho-Ro, Jinju-Si, Gyeongsangnam-Do 52851, Korea
Micro/Bio/Nanofluidics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0495, Japan
Department of Polymer Science and Engineering, Chonnam National University, Gwangju 61186, Korea
Fibrous Ceramics and Aerospace Materials Center, Korea Institute of Ceramic Engineering and Technology, 101 Soho-Ro, Jinju-Si, Gyeongsangnam-Do 52851, Korea
Authors to whom correspondence should be addressed.
Nanomaterials 2019, 9(11), 1530; https://doi.org/10.3390/nano9111530
Received: 24 September 2019 / Revised: 24 October 2019 / Accepted: 25 October 2019 / Published: 27 October 2019
The localized surface plasmon resonance (LSPR) sensitivity of metal nanostructures is strongly dependent on the interaction between the supporting substrate and the metal nanostructure, which may cause a change in the local refractive index of the metal nanostructure. Among various techniques used for the development of LSPR chip preparation, solid-state dewetting of nanofilms offers fast and cost effective methods to fabricate large areas of nanostructures on a given substrate. Most of the previous studies have focused on the effect of the size, shape, and inter-particle distance of the metal nanostructures on the LSPR sensitivity. In this work, we reveal that the silicon-based supporting substrate influences the LSPR associated refractive index sensitivity of gold (Au) nanostructures designed for sensing applications. Specifically, we develop Au nanostructures on four different silicon-based ceramic substrates (Si, SiO2, Si3N4, SiC) by thermal dewetting process and demonstrate that the dielectric properties of these ceramic substrates play a key role in the LSPR-based refractive index (RI) sensitivity of the Au nanostructures. Among these Si-supported Au plasmonic refractive index (RI) sensors, the Au nanostructures on the SiC substrates display the highest average RI sensitivity of 247.80 nm/RIU, for hemispherical Au nanostructures of similar shapes and sizes. Apart from the significance of this work towards RI sensing applications, our results can be advantageous for a wide range of applications where sensitive plasmonic substrates need to be incorporated in silicon based optoelectronic devices.