Controlling the electronic bands of a 2D semiconductor by force microscopy

Araújo, D.; Almeida, Rodrigo Queiros de; Gadelha, Andreij C.; Rezende, Natália P.; Salomão, Francisco Carlos Carneiro Soares; Silva, Francisco Wellery Nunes; Campos, Leonardo; Barros, Eduardo B.

doi:10.1088/2053-1583/aba5cb

Cited by 6 publications

(3 citation statements)

References 57 publications

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“…where k is the cantilever stiffness (calibrated prior experiments) and Z the sample perpendicular direction. While IV curves at low loads exhibited a semiconductor type behavior consistent with previous works [34,35], the IV curves evolve to linear dependence at high loads, consistent with a metallic phase. We checked the reliability of our electrical contacts by performing similar experiments in the nearby graphene surface where linear IVs were obtained at pressures under 5 GPa (see SI2 for further information).…”

Section: Resultssupporting

confidence: 88%

Low resistance electrical contacts to few-layered MoS₂ by local pressurization

Manzanares-Negro¹,

Quan²,

Rassekh³

et al. 2023

2D Mater.

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The performance of electronic and optoelectronic devices is dominated by charge carrier injection through metal–semiconductor contacts. Therefore, creating low-resistance electrical contacts is one of the most critical challenges to the development of devices based on new materials, especially in the case of two-dimensional semiconductors. Here, we report a strategy to reduce contact resistance to MoS2 via local pressurization. We make electrical contacts using an Atomic Force Microscopy tip and apply variable pressure ranging from 0 to 25 GPa. By measuring transverse electronic transport properties, we show that MoS2 under pressure undergoes a reversible semiconducting-metallic transition. Planar devices in field effect configuration with electrical contacts performed at pressures above ~15 GPa show an up to 30-fold reduced contact resistance and an up to 25-fold improved field-effect mobility when compared to those measured at low pressure. Theoretical simulations show that this enhanced performance is due to an improved charge injection to the MoS2 semiconductor channel through the metallic MoS2 phase obtained by pressurization. Our results suggest a novel strategy for realizing improved contacts to MoS2 devices by local pressurization and to explore emergent phenomena under mechano-electric modulation.

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Section: Resultssupporting

confidence: 88%

Low resistance electrical contacts to few-layered MoS₂ by local pressurization

Manzanares-Negro¹,

Quan²,

Rassekh³

et al. 2023

2D Mater.

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“…Indeed, de Araújo et al studied the change in Schottky barrier as a function of applied force (pressure) in Ref. [28], finding that SBH changes at a rate of 0.21(for a few layers MoS2), 0.23 (for three layers MoS2), and 0.78 (for two layers MoS2) meV nN -1 .…”

Section: Introductionmentioning

confidence: 99%

“…A change in pressure will change interlayer distances which in turn will affect the tight-binding hopping matrix elements as well as the DOS, so that one expects significant changes in the SBH as well as in transmission as a function of pressure. Indeed, de Araújo et al studied the change in Schottky barrier as a function of applied force (pressure), [28] finding that SBH changes at a rate of 0.21 (for a few layers MoS 2 ), 0.23 (for three layers MoS 2 ), and 0.78 (for two layers MoS 2 ) meV nN −1 .…”

Section: Introductionmentioning

confidence: 99%

Vertical Heterostructures between Transition‐Metal Dichalcogenides—A Theoretical Analysis of the NbS2/WSe2 Junction

Golsanamlou

Kumari

Sementa

et al. 2022

Adv Elect Materials

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Low-dimensional metal-semiconductor vertical heterostructures (VH) are promising candidates in the search of electronic devices at the extreme limits of miniaturization. Within this line of research, here we present a theoretical/computational study of the NbS2/WSe2 metalsemiconductor vertical hetero-junction using density functional theory (DFT) and conductance simulations. We first construct atomistic models of the NbS2/WSe2 VH considering all the five possible stacking orientations at the interface, and we conduct DFT and quantum-mechanical (QM) scattering simulations to obtain information on band structure and transmission coefficients. We then carry out an analysis of the QM results in terms of electrostatic potential, fragment decomposition, and band alignment. The behavior of transmission expected from this analysis is in excellent agreement with, and thus fully rationalizes, the DFT results, and the peculiar doublepeak profile of transmission. Finally, we use maximally localized Wannier functions, projected density of states (PDOS), and a simple analytic formula to predict and explain quantitatively the differences in transport in the case of epitaxial misorientation. Within the class of Transition-Metal Dichalcogenide systems, the NbS2/WSe2 vertical heterostructure exhibits a wide interval of finite transmission and a double-peak profile, features that could be exploited in applications.

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Strain Driven Electrical Bandgap Tuning of Atomically Thin WSe₂

Islam,

Nicholson,

Barri

et al. 2024

Adv Elect Materials

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Tuning electrical properties of 2D materials through mechanical strain has predominantly focused on n‐type 2D materials like MoS2 and WS2, while p‐type 2D materials such as WSe2 remain relatively unexplored. Here, the impact of controlled mechanical strain on the electron transport characteristics of both mono and bi‐layer WSe2 is studied. Through coupling atomic force microscopy (AFM) nanoindentation techniques and conductive AFM, the ability to finely tune the electronic band structure of WSe2 is demonstrated. The research offers valuable mechanistic insights into understanding how WSe2's electronic properties respond to mechanical strain, a critical prerequisite for the development of flexible photoelectronic devices. It is also observed that under high pressure, the AFM tip/monolayer WSe2/metal substrate junction transitions from Schottky to Ohmic contact, attributed to significant charge injection from the substrate to the WSe2. These findings are significant for designing efficient metal/semiconductor contact in thin and flexible PMOS (p‐type Metal–Oxide–Semiconductor) devices.

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Controlling the electronic bands of a 2D semiconductor by force microscopy

Cited by 6 publications

References 57 publications

Low resistance electrical contacts to few-layered MoS₂ by local pressurization

Low resistance electrical contacts to few-layered MoS₂ by local pressurization

Vertical Heterostructures between Transition‐Metal Dichalcogenides—A Theoretical Analysis of the NbS2/WSe2 Junction

Strain Driven Electrical Bandgap Tuning of Atomically Thin WSe₂

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Controlling the electronic bands of a 2D semiconductor by force microscopy

Cited by 6 publications

References 57 publications

Low resistance electrical contacts to few-layered MoS2 by local pressurization

Low resistance electrical contacts to few-layered MoS2 by local pressurization

Vertical Heterostructures between Transition‐Metal Dichalcogenides—A Theoretical Analysis of the NbS2/WSe2 Junction

Strain Driven Electrical Bandgap Tuning of Atomically Thin WSe2

Contact Info

Product

Resources

About

Low resistance electrical contacts to few-layered MoS₂ by local pressurization

Low resistance electrical contacts to few-layered MoS₂ by local pressurization

Strain Driven Electrical Bandgap Tuning of Atomically Thin WSe₂