Carbon Vacancy Assisted Contact Resistance Engineering in Graphene FETs

Kumar, Jeevesh; Meersha, Adil; Variar, Harsha B.; Mishra, Abhishek; Shrivastava, Mayank

doi:10.1109/ted.2022.3151033

Cited by 8 publications

(8 citation statements)

References 36 publications

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“…Figure 7 reflects that the band structure has more trap states once the metal interacts with TMDs in the presence of the chalcogen vacancy. Thus, the chalcogen vacancy at the metal−TMD interface can play a key role in MIGS-assisted contact resistance engineering at the interface as demonstrated by Ansh et al 20 for TMDs and by Kumar et al 17 for graphene.…”

Section: ■ Results and Discussionmentioning

confidence: 98%

“…This chalcogen vacancy can perturb the chemistry of the materials with external agents . Interestingly, this vacancy can also be a contact engineering tool, as explored in other 2D materials like graphene . Thus, it is worth investigating the role of the chalcogen point vacancy in the interactions between metals and TMDs.…”

Section: Resultsmentioning

confidence: 99%

“…25 Interestingly, this vacancy can also be a contact engineering tool, as explored in other 2D materials like graphene. 17 Thus, it is worth investigating the role of the chalcogen point vacancy in the interactions between metals and TMDs. All the explored pristine combinations were optimized for minimum energy after one chalcogen vacancy in the TMDs (Figure 5).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…However, a systematic study of metal–TMD interaction chemistry and its role in metal-induced gap states (MIGSs) has not been explored in detail yet. Besides, the scope of vacancy-assisted orbital overlap-based contact resistance engineering, like graphene, − is yet to be explored for TMDs at the atomic level. Ansh et al , used MIGSs and defect-induced gap states (DIGSs) as engineering tools, drastically reducing contact resistance at the TMD–metal interfaces.…”

Section: Introductionmentioning

confidence: 99%

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Role of Chalcogen Defect Introducing Metal-Induced Gap States and Its Implications for Metal–TMDs’ Interface Chemistry

Kumar

Shrivastava

2023

ACS Omega

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The contact resistance of the transition metal dichalcogenide (TMD) devices is not comparable to that of their silicon counterparts, probably due to a lack of clarity in their interface chemistry. Looking beyond the conventional Schottky−Mott rule, the metal chalcogen orbital overlaps, tunnel barrier, and metal-induced gap states (MIGSs) are crucial factors determining different metals' contact properties with TMDs. Exploring their properties helps TMDs' contact resistance engineering, driven mainly by their orbital overlaps and perturbing parameters. This work presents the interface chemistry of TMDs (MoS 2 , MoSe 2 , WS 2 , and WSe 2 ) with different metals (Au, Cr, Ni, and Pd) in detail using density functional theory computations. Additionally, the work discusses the role of the chalcogen vacancy and interstitial defects in the metal−TMD interactions and corresponding MIGS features. The investigations reveal that Au does not show any significant MIGS due to its weak interactions with all the TMDs. However, other investigated metals have a strong affinity with TMDs, making significant MIGS contributions. All the metals offer n-type doping characteristics to TMDs due to valence charge transfer from the metals toward TMDs. The chalcogen vacancy boosts the orbital overlaps of the TMDs with all the metals. The vacancy reduces metal−TMD interfacial distance, which can be a promising technique to reduce the tunnel barrier and contact resistance. The MIGS and defect-induced gap states (DIGSs) reflect the possibility of Fermi-level pinning in the TMDs' contacts with Cr, Ni, and Pd. Besides, the work discloses that the chalcogen vacancy converts an n-type Pd−TMD interface into p-type due to reverse charge transfer after the vacancy. Chalcogen interstitial impurity also helps with contact resistance engineering for some metal−TMD systems by reducing the bond distance of the metal TMDs. Our study highlights the possibility of defect-assisted and MIGS-based contact engineering at the metal−TMD interfaces.

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Section: ■ Results and Discussionmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Role of Chalcogen Defect Introducing Metal-Induced Gap States and Its Implications for Metal–TMDs’ Interface Chemistry

Kumar

Shrivastava

2023

ACS Omega

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“…According to the previous results, these vacancies increase the carrier transmission probabilities at the interface, resulting in a reduced contact resistance. 52 Thus, the Se vacancies generated in the rst RTA-annealed PtSe 2 lm (Fig. 2f) reduced the contact resistance; however, the Schottky barrier effect still existed because of the Pt and Ag electrodes, which were deposited onto the rst RTA-annealed PtSe 2 lm.…”

Section: Discussionmentioning

confidence: 99%

Intrinsic Seebeck coefficients of 2D polycrystalline PtSe₂semiconducting films through two-step annealing

et al. 2023

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Defect engineering the electronic and optoelectronic properties of heterostructure of MoSSe/PbS (111)

Zhang

Huang

Liu

et al. 2023

J. Phys.: Condens. Matter

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The structural, electronic and optical properties of MoSSe, PbS (111) and MoSSe/PbS (111) have been studied by the first-principles calculations, and the effect of VS on electronic and optical properties of MoSSe/PbS (111). When PbS (111) is stacked on MoSSe, an internal electric field and ohmic contact are formed at interlayer, and exhibited metal property. Compared with MoSSe and PbS (111) monolayer, MoSSe/PbS (111) heterostructure has higher absorption coefficients. Further analysis shows that this can be attributed to the orbital hybridization between the heterostructure layers. When VS is introduced, spin splitting occurs, making the spin-down channel below the Fermi level and inducing half-metallicity. What’s more, VsMoSSe/PbS (111) still performances better optical absorption coefficient. Based on these findings, the heterogeneous structures and defects not only affect the electronic properties, but also can be used as an effective method to regulate the electrical and optical properties, providing useful theoretical guidance for further experimental studies.

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Carbon Vacancy Assisted Contact Resistance Engineering in Graphene FETs

Cited by 8 publications

References 36 publications

Role of Chalcogen Defect Introducing Metal-Induced Gap States and Its Implications for Metal–TMDs’ Interface Chemistry

Role of Chalcogen Defect Introducing Metal-Induced Gap States and Its Implications for Metal–TMDs’ Interface Chemistry

Intrinsic Seebeck coefficients of 2D polycrystalline PtSe₂semiconducting films through two-step annealing

Defect engineering the electronic and optoelectronic properties of heterostructure of MoSSe/PbS (111)

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Carbon Vacancy Assisted Contact Resistance Engineering in Graphene FETs

Cited by 8 publications

References 36 publications

Role of Chalcogen Defect Introducing Metal-Induced Gap States and Its Implications for Metal–TMDs’ Interface Chemistry

Role of Chalcogen Defect Introducing Metal-Induced Gap States and Its Implications for Metal–TMDs’ Interface Chemistry

Intrinsic Seebeck coefficients of 2D polycrystalline PtSe2semiconducting films through two-step annealing

Defect engineering the electronic and optoelectronic properties of heterostructure of MoSSe/PbS (111)

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Intrinsic Seebeck coefficients of 2D polycrystalline PtSe₂semiconducting films through two-step annealing