Dielectric Dispersion and High Field Response of Multilayer Hexagonal Boron Nitride

Ahmed, Faisal; Heo, Sungho; Yang, Zheng; Ho, Chang Won; Lee, Ho‐In; Taniguchi, Takashi; Hone, James; Lee, Byoung Hun; Yoo, Won Jong

doi:10.1002/adfm.201804235

Cited by 44 publications

(42 citation statements)

References 40 publications

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“…Their result showed that the center of graphene device is heated up to 1050K temperature and lateral ends are relatively cooler as the metallic electrodes function as heat sink, as shown in Figure 1(b). Similarly, operating temperature of 2D semiconducting materials MoS 2 and black phosphorus was also reported by micro-Raman spectroscopy [4,[9][10][11]. In another study, Grosse et.…”

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confidence: 54%

Joule Heating in Two-dimensional Materials Based Transistors

Ahmed¹

2019

RDMS

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Transistor is considered as a building block for electronic circuitry, as it is used to control the flow of electric current across its semiconducting channel while applying potential difference along its metallic electrodes (the source and the drain). The flow of current is regulated by a third electrode called the gate, that is separated from a semiconducting channel by an electrically insulating material, as shown schematically in Figure 1(a). When a large amount of electric field (F) [electric potential (V) normalized by channel length (L), F = V/L], is applied to a transistor, the kinetic energy of electronic charge carriers in semiconducting channel increases, resulting in the aggressive interaction of carriers with each other and with immediate environment. These charge collision events in association with atomic oscillations, also called phonons, increase the device operating temperature, and this effect is called Joule heating [1]. The extent of Joule/thermal power (P) generated depends on the electrical resistance (R) of a material and the square of current (I) passed across it, as P=I 2 R [2]. In a typical integrated circuit, there are over a billion transistors that generate significant amount of thermal energy. If the Joule energy is not dissipated properly, it may lead to malfunction or eventual burning of transistors hence circuits [3].

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confidence: 54%

Joule Heating in Two-dimensional Materials Based Transistors

Ahmed¹

2019

RDMS

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“…(where = 3.5 is the relative permittivity of hBN 25,26 and ℎ is the total thickness between the graphene gates in nm), achieved by varying gate voltages, . The domain configuration, prepared by applying 0 −1 = 2.2 V/nm, stays the same upon removing the gate voltage ( = 0) (Fig.…”

Section: Main Textmentioning

confidence: 99%

Interfacial ferroelectricity in marginally twisted 2D semiconductors

Weston

Castanon

Enaldiev

et al. 2021

Preprint

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Twisted heterostructures of two-dimensional crystals offer almost unlimited scope for the design of novel metamaterials. Here we demonstrate a room-temperature ferroelectric semiconductor that is assembled using mono- or few- layer MoS2. These van der Waals heterostructures feature broken inversion symmetry, which, together with the asymmetry of atomic arrangement at the interface of two 2D crystals, enables ferroelectric domains with alternating out-of-plane polarisation arranged into a twist-controlled network. The latter can be moved by applying out-of-plane electrical fields, as visualized in situ using channelling contrast electron microscopy. The interfacial charge transfer for the observed ferroelectric domains is quantified using Kelvin probe force microscopy and agrees well with theoretical calculations. The movement of domain walls and their bending rigidity also agrees well with our modelling results. Furthermore, we demonstrate proof-of-principle field-effect transistors, where the channel resistance exhibits a pronounced hysteresis governed by pinning of ferroelectric domain walls. Our results show a potential venue towards room temperature electronic and optoelectronic semiconductor devices with built-in ferroelectric memory functions.

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“…Ahmed et al reported the dispersion characteristics of multi-layer h-BNs at different thickness and temperatures, demonstrating its potential as a dielectric material. 22 The thickness (d) of h-BN was determined to be 41 nm by AFM analysis. SEM imaging of the as-fabricated (pristine) sample conrmed that the top electrode was electrically isolated from the bottom electrode by the h-BN nanolayer (Fig.…”

Section: Resultsmentioning

confidence: 99%