Tunneling Spectroscopy for Electronic Bands in Multi-Walled Carbon Nanotubes with Van Der Waals Gap

Choi, Dong-Hwan; Lee, Seung Mi; Jeong, Du-Won; Lee, Jun Young; Ha, Dong-Woo; Bae, Myung‐Ho; Kim, Ju‐Jin

doi:10.3390/molecules26082128

Cited by 3 publications

(3 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The purpose of this SG electrode is to provide an additional means of tuning the CNT band, complementing the effect of the back gate. To perform the vdW tunneling spectroscopy, we selected In metal as the contact metal for the CNT, leading to the establishment of a vdW vacuum gap at the interface between the In contact and the CNT. − Notably, unlike previous investigations in which In metal was used for all contacts, this study selectively introduces an In contact at a single contact. The counterpart contact is formed by Pd metal to form an Ohmic contact, as shown in Figure (see the Methods Section for details) .…”

Section: Resultsmentioning

confidence: 99%

“…Figure 2a further reveals that the conductance peak lines become steeper as V bg is greater than −35 V at V b > 0 V. A similar trend is observed for V b < 0 V. The change in slope near the bandgap edge is associated with variations in the width of the Schottky barrier formed at the junction between the CNT and the In metal contact. 21,22 Thus, the nonlinear slopes of the conductance peak lines are likely due to a combination of band shifting and modification in the Schottky barrier as V bg is varied. Additionally, contact resistances at both the Pd/CNT and In/CNT junctions increase abruptly due to the increment of the CNT channel resistance in the depletion region.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Role of Quantum Capacitance in a Carbon Nanotube Tunneling Device

Kim,

Myoung,

Bae

et al. 2024

ACS Appl. Electron. Mater.

Self Cite

View full text Add to dashboard Cite

Quantum capacitance is directly linked to the electronic density of states near the Fermi level in electronic devices and imposes constraints on the vertical scaling of fieldeffect transistors. In tunneling devices, the quantum capacitances associated with tunnel contacts strongly influence the tunneling spectrum. Here, we investigate a direct relationship between quantum capacitance and electronic density of states in a carbon nanotube device on the basis of van der Waals tunneling spectroscopy conducted on a carbon nanotube with a single indium contact. We observe multiple tunneling conductance peaks corresponding to the van Hove singularities of subbands in the nanotube. We demonstrate that quantum capacitances at these singularities of distinct subbands directly affect the coupling strength between the applied voltages and the effective potential within the nanotube, leading to observable changes in the slopes of the conductance peak lines in a plot of conductance as a function of the bias and gate voltages. Our theoretical model based on the quantum capacitance of a nanotube agrees with the experimental observations.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Role of Quantum Capacitance in a Carbon Nanotube Tunneling Device

Kim,

Myoung,

Bae

et al. 2024

ACS Appl. Electron. Mater.

Self Cite

View full text Add to dashboard Cite

show abstract

“…However, the vdW contact at a cryogenic temperature could provide a vacuum tunneling gap with a high contact resistance that makes the flow of current sensitive to the electronic DOS at the interface. Indeed, vdW gap tunneling spectroscopy based on a field-effect transistor (FET) design with carbon nanotubes (CNTs) with In metal contacts was demonstrated, recently 16 , 17 . In this previous work, the local conductance peaks observed in the conductance vs bias voltage plot were shown to originate from the van Hove singularities corresponding to the sub-band structures of semiconducting and metallic CNTs.…”

Section: Introductionmentioning

confidence: 99%

Indium-contacted van der Waals gap tunneling spectroscopy for van der Waals layered materials

Choi

Min

Hong

et al. 2021

Sci Rep

Self Cite

View full text Add to dashboard Cite

The electrical phase transition in van der Waals (vdW) layered materials such as transition-metal dichalcogenides and Bi2Sr2CaCu2O8+x (Bi-2212) high-temperature superconductor has been explored using various techniques, including scanning tunneling and photoemission spectroscopies, and measurements of electrical resistance as a function of temperature. In this study, we develop one useful method to elucidate the electrical phases in vdW layered materials: indium (In)-contacted vdW tunneling spectroscopy for 1T-TaS2, Bi-2212 and 2H-MoS2. We utilized the vdW gap formed at an In/vdW material interface as a tunnel barrier for tunneling spectroscopy. For strongly correlated electron systems such as 1T-TaS2 and Bi-2212, pronounced gap features corresponding to the Mott and superconducting gaps were respectively observed at T = 4 K. We observed a gate dependence of the amplitude of the superconducting gap, which has potential applications in a gate-tunable superconducting device with a SiO2/Si substrate. For In/10 nm-thick 2H-MoS2 devices, differential conductance shoulders at bias voltages of approximately ± 0.45 V were observed, which were attributed to the semiconducting gap. These results show that In-contacted vdW gap tunneling spectroscopy in a fashion of field-effect transistor provides feasible and reliable ways to investigate electronic structures of vdW materials.

show abstract

Single-particle states spectroscopy in individual carbon nanotubes with an aid of tunneling contacts

Matyushkin

Moskotin

Rogov

et al. 2022

Applied Physics Letters

View full text Add to dashboard Cite

Recent studies have demonstrated that the band structure of a carbon nanotube (CNT) depends not only on its geometry but also on various factors such as atmosphere chemical composition and dielectric environment. Systematic studies of these effects require an efficient tool for an in situ investigation of a CNT band structure. In this work, we fabricate tunneling contacts to individual semiconducting carbon nanotubes through a thin layer of alumina and perform tunneling spectroscopy measurements. We use field-effect transistor configuration with four probe contacts (two tunnel and two ohmic) and bottom gates. Bandgap values extracted from tunneling measurements match the values estimated from the diameter value within the zone-folding approximation. We also observe the splitting of Van-Hove singularities of the density of states under an axial magnetic field.

show abstract

Tunneling Spectroscopy for Electronic Bands in Multi-Walled Carbon Nanotubes with Van Der Waals Gap

Cited by 3 publications

References 21 publications

Role of Quantum Capacitance in a Carbon Nanotube Tunneling Device

Role of Quantum Capacitance in a Carbon Nanotube Tunneling Device

Indium-contacted van der Waals gap tunneling spectroscopy for van der Waals layered materials

Single-particle states spectroscopy in individual carbon nanotubes with an aid of tunneling contacts

Contact Info

Product

Resources

About