# Advanced engineering of single-crystal gold nanoantennas

## TL;DR

This paper introduces a novel nanofabrication process for creating single-crystal gold nanoantennas using dry etching of synthesized gold crystals, offering improved optical properties and design flexibility over traditional methods.

## Contribution

The authors present a new dry etching technique for fabricating single-crystal gold nanoantennas, enabling better optical performance and broader material applicability compared to existing methods.

## Key findings

- Single-crystal nanoantennas exhibit reduced plasmonic losses.
- The process allows fabrication with standard electron-beam lithography.
- Applicable to metals like silver and copper.

## Abstract

A nanofabrication process for realizing optical nanoantennas carved from a single-crystal gold plate is presented in this communication. The method relies on synthesizing two-dimensional micron-size gold crystals followed by the dry etching of a desired antenna layout. The fabrication of single-crystal optical nanoantennas with standard electron-beam lithography tool and dry etching reactor represents an alternative technological solution to focused ion beam milling of the objects. The process is exemplified by engineering nanorod antennas. Dark-field spectroscopy indicates that optical antennas produced from single crystal flakes have reduced localized surface plasmon resonance losses compared to amorphous designs of similar shape. The present process is easily applicable to other metals such as silver or copper and offers a design flexibility not found in crystalline particles synthesized by colloidal chemistry.