Atomic-scale characterization of structural heterogeny in 2D TMD layers

Li, Hao; Yoo, Changhyeon; Ko, Tae-Jun; Kim, Jung Han; Jung, Yeonwoong

doi:10.1039/d1ma01013a

Cited by 9 publications

(4 citation statements)

References 95 publications

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“…The 0D defects (dopants and vacancies), 1D defects (inclusion and dislocations), grain boundaries, and van der Waals gaps are the main dopant-induced structural disorders. 90 This position, distribution, and disorder in materials, which affect the characteristics of the materials, can be identified by STEM analytical technique with atomic resolution. 91 The working principle of the STEM technique is based on the idea of the angular selection of the scattered signal, in which the detector collects only the electrons scattered to large angles and avoids the Bragg reflections.…”

Section: Characterization Techniquesmentioning

confidence: 99%

Insights into ZnO-based doped porous nanocrystal frameworks

Abebe

Murthy

2022

RSC Adv.

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Section: Characterization Techniquesmentioning

confidence: 99%

Insights into ZnO-based doped porous nanocrystal frameworks

Abebe

Murthy

2022

RSC Adv.

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“…Based on the advantages mentioned above, edge contacts are adopted for this study. Furthermore, the atomic-scale characterization of the interfaces has garnered interest in research over the past years [ 34 , 35 , 36 , 37 ], so the atomistic structural variation across the TMD/metal interfaces is also considered. The atomistic interfaces can be divided into two categories based on their structural variants: symmetric convex and concave edge contacts.…”

Section: Introductionmentioning

confidence: 99%

Impact of Rh, Ru, and Pd Leads and Contact Topologies on Performance of WSe2 FETs: A First Comparative Ab Initio Study

Chung,

Lin,

Liu

et al. 2024

Materials

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2D field-effect transistors (FETs) fabricated with transition metal dichalcogenide (TMD) materials are a potential replacement for the silicon-based CMOS. However, the lack of advancement in p-type contact is also a key factor hindering TMD-based CMOS applications. The less investigated path towards improving electrical characteristics based on contact geometries with low contact resistance (RC) has also been established. Moreover, finding contact metals to reduce the RC is indeed one of the significant challenges in achieving the above goal. Our research provides the first comparative analysis of the three contact configurations for a WSe2 monolayer with different noble metals (Rh, Ru, and Pd) by employing ab initio density functional theory (DFT) and non-equilibrium Green’s function (NEGF) methods. From the perspective of the contact topologies, the RC and minimum subthreshold slope (SSMIN) of all the conventional edge contacts are outperformed by the novel non-van der Waals (vdW) sandwich contacts. These non-vdW sandwich contacts reveal that their RC values are below 50 Ω∙μm, attributed to the narrow Schottky barrier widths (SBWs) and low Schottky barrier heights (SBHs). Not only are the RC values dramatically reduced by such novel contacts, but the SSMIN values are lower than 68 mV/dec. The new proposal offers the lowest RC and SSMIN, irrespective of the contact metals. Further considering the metal leads, the WSe2/Rh FETs based on the non-vdW sandwich contacts show a meager RC value of 33 Ω∙μm and an exceptional SSMIN of 63 mV/dec. The two calculated results present the smallest-ever values reported in our study, indicating that the non-vdW sandwich contacts with Rh leads can attain the best-case scenario. In contrast, the symmetric convex edge contacts with Pd leads cause the worst-case degradation, yielding an RC value of 213 Ω∙μm and an SSMIN value of 95 mV/dec. While all the WSe2/Ru FETs exhibit medium performances, the minimal shift in the transfer curves is interestingly advantageous to the circuit operation. Conclusively, the low-RC performances and the desirable SSMIN values are a combination of the contact geometries and metal leads. This innovation, achieved through noble metal leads in conjunction with the novel contact configurations, paves the way for a TMD-based CMOS with ultra-low RC and rapid switching speeds.

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“…These materials include pnictogens, carbon nitride (C 3 N 4 ), hexagonal boron nitride (h-BN), layered double hydroxide (LDH), metal chalcogenide, MBenes and MXenes. [21][22][23][27][28][29][30][31][32] Their applications are broad as they can be used in electronic devices, energy storage, sensors, and catalytic reactions. One strategy in the utilization of 2D materials has been widened by depositing a zero-dimensional (0D), one-dimensional (1D) or three-dimension (3D) layer, or stacking different 2D materials to alter the properties, resulting in a so-called ''heterostructure''.…”

Section: Introductionmentioning

confidence: 99%