Optical Signatures of Dirac Electrodynamics for hBN-Passivated Silicene on Au(111)

Genser, Jakob; Nazzari, Daniele; Ritter, Viktoria; Bethge, Ole; Watanabe, Kenji; Taniguchi, Takashi; Bertagnolli, E.; Bechstedt, F.; Lugstein, Alois

doi:10.1021/acs.nanolett.1c01440

Cited by 14 publications

(11 citation statements)

References 59 publications

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“…47,48 Nevertheless, it has been shown that the Dirac features are preserved even under a high deformation of the silicene layer. 47,49 As mentioned earlier, the structural modification of silicene could have been triggered by the weak interaction with the fluoride layer. It has been observed that, through the intercalation of F − ions in a CaSi 2 crystal, silicene bilayers are obtained.…”

Section: ■ Discussionmentioning

confidence: 91%

“…We note that this structural change does not depend on the amount of deposited CaF 2 but just on the interaction with the capping material. It can be expected that such a structural modification will also have an impact on the electronic properties of the 2D layer. , Nevertheless, it has been shown that the Dirac features are preserved even under a high deformation of the silicene layer. , …”

Section: Discussionmentioning

confidence: 99%

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Epitaxial Growth of Crystalline CaF₂ on Silicene

Nazzari¹,

Genser²,

Ritter³

et al. 2022

ACS Appl. Mater. Interfaces

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Silicene is one of the most promising two-dimensional (2D) materials for the realization of next-generation electronic devices, owing to its high carrier mobility and band gap tunability. To fully control its electronic properties, an external electric field needs to be applied perpendicularly to the 2D lattice, thus requiring the deposition of an insulating layer that directly interfaces silicene, without perturbing its bidimensional nature. A promising material candidate is CaF2, which is known to form a quasi van der Waals interface with 2D materials as well as to maintain its insulating properties even at ultrathin scales. Here we investigate the epitaxial growth of thin CaF2 layers on different silicene phases by means of molecular beam epitaxy. Through electron diffraction images, we clearly show that CaF2 can be grown epitaxially on silicene even at low temperatures, with its domains fully aligned to the lattice of the underlying 2D structure. Moreover, in situ X-ray photoelectron spectroscopy data evidence that, upon CaF2 deposition, no changes in the chemical state of the silicon atoms can be detected, proving that no Si–Ca or Si–F bonds are formed. This clearly shows that the 2D layer is pristinely preserved underneath the insulating layer. Polarized Raman experiments show that silicene undergoes a structural change upon interaction with CaF2; however, it retains its two-dimensional character without transitioning to a sp3-hybridized silicon. For the first time, we have shown that CaF2 and silicene can be successfully interfaced, paving the way for the integration of silicon-based 2D materials in functional devices.

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Section: ■ Discussionmentioning

confidence: 91%

Section: Discussionmentioning

confidence: 99%

Epitaxial Growth of Crystalline CaF₂ on Silicene

Nazzari¹,

Genser²,

Ritter³

et al. 2022

ACS Appl. Mater. Interfaces

Self Cite

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“…According to the method described in Ref. 20 and the compatibility of silicene with h-BN encapsulation 27 , we present the method shown in Fig. 9 in order to fabricate the proposed OMOSFET.…”

Section: Fabrication Processmentioning

confidence: 99%

“…Generally, in addition to Al 2 O 3 , h-BN is also used between silicene and oxide layers to maintain the structure, high carrier mobility 26 , and optical properties of silicene 27 . The h-BN layer as a buffer is important in the fabrication of devices based on intrinsic silicene 24 .…”

Section: Introductionmentioning

confidence: 99%

First designing of a silicene-based optical MOSFET with outstanding performance

Emami-Nejad

Mir

Lorestaniweiss

et al. 2023

Sci Rep

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Miniaturized integrated optical devices with low power consumption have long been considered hot candidates for plasmonic applications. While 2D materials such as graphene have been proposed for this purpose, they suffer from large propagation loss and low controllability at room temperature. Here, a silicene-based optical MOSFET with excellent performance is designed to achieve integrated circuit optical technology. The designed device is comprised of a silicene optical waveguide whose switching operation is performed by a gate and has a structure similar to an enhancement MOSFET with a formed channel. Unlike graphene, the surface conductivity of silicene can be controlled by both chemical potential and an electric field perpendicular to its surface. This unique feature of silicene is used to design and simulate an optical-MOSFET with transverse electric polarization at 300 K. The salient characteristics of the optical device include its nanoscale dimensions, ultra-low insertion loss of 0.13 dB, infinite extinction ratio, and quality factor of 688, proposing it as a promising tool for optical integration.

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“…6,7 Among 2D-Xenes, silicene attracts particular attention because of its unique properties and technological potential. 8 Similar to graphene, silicene demonstrates signatures of Dirac electrodynamics; 9 its applications range from field-effect transistors 10 to Li-ion batteries. 11 It could be a wonder material but there is a catch – silicene and other 2D-Xenes exhibit high chemical reactivity making them difficult to handle.…”

Section: Introductionmentioning

confidence: 99%