Nanodevices at terahertz frequency based on 2D materials

Abstract

Artificial semiconductor heterostructures played a pivotal role in modern electronic and photonic technologies, providing a highly effective mean for the manipulation and control of carriers, from the visible to the terahertz frequency range. Despite their exceptional versatility, they commonly require challenging epitaxial growth procedures, due to the need of clean and abrupt interfaces, lattice matching or limited and controlled lattice mismatch, which proved to be major obstacles for the development of room-temperature devices, like sources, detectors or modulators, especially in the far-infrared. The discovery of graphene and the related fascinating capabilities have triggered an unprecedented interest in inorganic two-dimensional materials. Layered materials such as graphene, hexagonal boron nitride, transition metal dichalcogenides, and the more recently re-discovered black phosphorus display an exceptional technological potential for engineering nano-electronic and nanophotonic devices and components 'by design', offering a unique platform for developing devices with a variety of properties. Here, I review our latest achievements in the design and developments of graphene based nanodetectors, saturable absorbers and near field probes operating across the farinfrared.

Bi-dimensional materials for THz frequency nanodevices

“…The inherent electrical and thermal in-plane anisotropy of BP can be indeed exploited to selectively control the detection dynamics in the BP channel, with state-of-the-art performances. RT operation with ~ 20000 signal-tonoise ratio [2], NEPs ≤10 -9 W/Hz 1/2 ), responsivities > 10 V/W [6], and response times of a few µs [7].…”

“…THz saturable absorption has been recently demonstrated in graphene [9,7]. By transfer coating and ink-jet printing 50 layers (randomly distributed) of graphene films prepared by liquid phase exfoliation of graphite and through a combination of open-aperture z-scan experiments and Fourier transform infrared (FTIR) spectroscopy, 80% transparency modulation at 3.4 THz has been reported [9].…”

“…Alternative reports on THz graphene saturable absorbers include multi-layer graphene grown on the carbon-face of silicon carbide, allowing a maximum absorption modulation of ~10%, inherently limited by disorder [10], or multilayer graphene films, grown via CVD on Nickel, in which a 10% transparency modulation, dominated by intraband phenomena has been shown [7].…”

Advances in Liquid‐Phase and Intercalation Exfoliations of Transition Metal Dichalcogenides to Produce 2D Framework

“…[5,8,9] It has been estimated that 700 2D materials are stable, but others are still to be outlined (source: 2dmaterialsweb.org). [10,11] 2D materials are reflected as superstars of the material world and can modernize to every aspect from digital electronics to energy storage and vital to their incredible physical/electronic properties. [2,12,13] Encompassing layers at atomically thick, these crystalline materials are meritoriously over whole surface, it gives them not only a vast surface area for molecular interaction and reaction with physical forces but also influenced quantum confinement effects which provide properties that can vary drastically from their 3D counterparts.…”

Chemical reactions on surfaces for applications in catalysis, gas sensing, adsorption-assisted desalination and Li-ion batteries: opportunities and challenges for surface science

“…53 Correspondingly, theoretical models accomplished a huge leap with the unceasing upgrading of computational capabilities, [54][55][56][57][58] including corrections for taking into account weak forces, 59,60 now enabling the prediction of chemical properties of surfaces and interfaces. [61][62][63][64] The advent of two-dimensional (2D) materials had a dramatic impact on research of materials, [65][66][67][68][69][70][71] so that most groups working on surface science moved their activities to match the current interests of the scientific community. Nevertheless, surface science should remain at the vanguard of both technological and scientific advances, also considering the higher relevance of surface phenomena in nanostructures.…”