Plasmonic Properties of Individual Gallium Nanoparticles

Abstract

Gallium is a plasmonic material offering ultraviolet to near-infrared tunability, facile and scalable preparation, and good stability of nanoparticles. In this work, we experimentally demonstrate the link between the shape and size of individual gallium nanoparticles and their optical properties. To this end, we utilize scanning transmission electron microscopy combined with electron energy loss spectroscopy. Lens-shaped gallium nanoparticles with a diameter between 10 and 200 nm were grown directly on a silicon nitride membrane using an effusion cell developed in house that was operated under ultra-highvacuum conditions. We have experimentally proven that they support localized surface plasmon resonances and their dipole mode can be tuned through their size from the ultraviolet to near-infrared spectral region. The measurements are supported by numerical simulations using realistic particle shapes and sizes. Our results pave the way for future applications of gallium nanoparticles such as hyperspectral absorption of sunlight in energy harvesting or plasmon-enhanced luminescence of ultraviolet emitters.

Single-step fabrication of liquid gallium nanoparticles via capillary interaction for dynamic structural colours

“…Recent advances have shown that Ga, a liquid metal with plasmonic properties on par with gold and silver 29,30 , and its alloys 31,32 allow for the fabrication of flexible, bendable, and mechanically reconfigurable devices 33,34 , including electronic devices 35 . Thus far, however, scaling down Ga structures to the nanoscale has remained challenging, owing to its large surface tension (708 mN m −1 ) at room temperature 36 , which prevents precise fabrication of sub-100 nm feature dimensions required for application in the visible domain.…”

On the unique temperature-dependent interplay of a B-exciton and its trion in monolayer MoSe2

“…Ga is chemically stable and follows the classical Drude-like dispersion from the ultraviolet regime to the infrared regime. 17 The melting temperature close to ambient conditions allows facile synthesis using vacuum deposition techniques even on soft polymers. This has enabled multiple flexible electronic device applications using Ga. 17,18 Thin native oxide (Ga 2 O 3 ) is self-passivating and provides the necessary chemical stability.…”

“…17 The melting temperature close to ambient conditions allows facile synthesis using vacuum deposition techniques even on soft polymers. This has enabled multiple flexible electronic device applications using Ga. 17,18 Thin native oxide (Ga 2 O 3 ) is self-passivating and provides the necessary chemical stability. These aspects generate immense interest in coupling novel low-dimensional semiconductors with surface plasmons of Ga, leading to applications in surface-enhanced Raman spectroscopy (SERS), transport and storage of energy, optical force enhancement, and measuring intramolecular distances in molecules.…”

“…These aspects generate immense interest in coupling novel low-dimensional semiconductors with surface plasmons of Ga, leading to applications in surface-enhanced Raman spectroscopy (SERS), transport and storage of energy, optical force enhancement, and measuring intramolecular distances in molecules. 7,12,18 The excellent optical properties of Ga 3,17 with the possibility of fine control of particle size using facile processing techniques 6 have motivated this research on integrating Ga nanoparticles with layered semiconductors. One of the possible applications of such interfaces can be to promote optical access and investigations of a non-dominant excited state (not the ground excitonic state) in a monolayer semiconductor and observing the particle population dynamics at different temperatures.…”

Toward the megapixel live electrooptic imaging technique

“…This feature is still highlighted among recently reported advanced electric field imaging techniques. [5][6][7][8][9][10][11][12] The LEI technique is based on two excellences of photonics, 13) ultra-parallel 14,15) and ultra-fast 16,17) properties, which are merged in an electrooptic (EO) sensor 18,19) shaped in the form of a plate. [20][21][22] The present status of the LEI technique is specified by its highest frequency of visualized waves, largest vision area, highest optical magnification ratio, highest spatial resolution, and maximum number of image pixels, which are 100 GHz, 2) 25 mm square, 3) 200, 2.8 μm, and 256 × 256 = 65 536, 23) respectively.…”