Thickness-Dependent Enhancement of Electronic Mobility of MoS<sub>2</sub> Transistors via Surface Functionalization

Nie, Changjiang; Zhang, Butian; Gao, Yuting; Yin, Mingming; Yi, Xin; Zhao, Chuanwen; Zhang, Youwei; Luo, Liang; Wang, Shun

doi:10.1021/acs.jpcc.0c02657

Cited by 18 publications

(19 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We next investigated the effect of two-step functionalization on the electrical transport of MoS 2 in back-gated FETs. The changes in electrical characteristics are consistent with our previous study, 34 in which we systematically investigated the possible origin of the increase in I on of the MoS 2 FETs after LA treatment by statistically analyzing more than 100 samples with 1−20 layers. We propose the enhancement is attributed to the reduction of charge impurity scattering that is caused by filling of S vacancies.…”

Section: Resultssupporting

confidence: 89%

“…In fact, these molecules linked to SVs provide an excellent bridge to further covalent bonding other kinds of molecules with given active groups. In our recent study, 34 we chemically bonded lipoic acid (LA) molecules to MoS 2 surfaces. This functionalization enhances the mobility of MoS 2 field-effect transistors (FETs) with a strong thickness dependence.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Tailoring the Fluorescent and Electronic Properties of 2H-MoS₂ by Step-by-Step Functionalization

et al. 2021

Self Cite

View full text Add to dashboard Cite

Two-dimensional layered MoS2 has attracted tremendous attention because of its unique physical and chemical properties and promising application prospects. To further expand its applications to areas such as gas sensing, biosensing, drug delivery, and photothermal therapy, surface functionalization has been employed to engineer its properties according to multiple perspectives. Herein, we demonstrate a scalable surface modification method to generate functionalized MoS2 flakes by the step-by-step covalent assembly of lipoic acid (LA) and fluorescein isothiocyanate (FITC) molecules. In our approach, reactive disulfide-containing LA molecules were first chemically bonded to the sulfur vacancies (SVs) of MoS2 surfaces. FITC was then linked to MoS2 through LA by a condensation reaction between the amino group of FITC and the carboxyl group of LA. It was demonstrated that the initial LA functionalization enhanced the electronic mobility via the filling of SVs, and the second-step functionalization with FITC induced electron doping of MoS2. Moreover, the covalent attachment of FITC decorated the PL spectrum of MoS2 with an additional green fluorescence at ∼530 nm. This strategy is a universal route to construct a versatile platform for chemical modification of functional groups and provides new opportunities of controlling the electronic and optical properties of transition-metal dichalcogenides.

show abstract

Section: Resultssupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Tailoring the Fluorescent and Electronic Properties of 2H-MoS₂ by Step-by-Step Functionalization

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…tributed to LA such as the band located at 3500 cm corresponding to O-H vibrations carboxylic group, the band at 2925 and 2850 cm −1 corresponding to CH2 and CH stretchin vibration and the band 1670 cm −1 and1434 cm −1 corresponding to C=O and C-O vibration respectively of carbonyl group [36]. All above mentioned bands are absent in the contr spectrum of MoS2.…”

Section: La-mos 2 Synthesis and Structural Characterizationmentioning

confidence: 94%

“…To confirm the presence of lipoic acid moieties on the MoS 2 surface, FT-IR analysis was performed. The spectra displayed in Figure 1b show the characteristic bands attributed to LA such as the band located at 3500 cm −1 corresponding to O-H vibrations of carboxylic group, the band at 2925 and 2850 cm −1 corresponding to CH 2 and CH stretching vibration and the band 1670 cm −1 and 1434 cm −1 corresponding to C=O and C-O vibrations, respectively of carbonyl group [36]. All above mentioned bands are absent in the control spectrum of MoS 2 .…”

Section: La-mos2/spce Surface Modification and Characterizationmentioning

confidence: 99%

Self-Assembled MoS2/ssDNA Nanostructures for the Capacitive Aptasensing of Acetamiprid Insecticide

2021

View full text Add to dashboard Cite

The aim of this work is to detect acetamiprid using electrochemical capacitance spectroscopy, which is widely used as a pesticide in agriculture and is harmful to humans. We have designed aptasensing platform based on the adsorption of a DNA aptamer on lipoic acid-modified MoS2 nano-sheets. The biosensor takes advantage of the high affinity of single-stranded DNA sequences to MoS2 nano-sheets. The stability of DNA on MoS2 nano-sheets is assured by covalent attachment to lipoic acid that forms self-assembled layer on MoS2 surface. The biosensor exhibits excellent capacitance performances owing to its large effective surface area making it interesting material for capacitive transduction system. The impedance-derived capacitance varies with the increasing concentrations of acetamiprid that can be attributed to the aptamer desorption from the MoS2 nanosheets facilitating ion diffusion into MoS2 interlayers. The developed device showed high analytical performances for acetamiprid detection on electrochemical impedance spectroscopy EIS- derived capacitance variation and high selectivity toward the target in presence of other pesticides. Real sample analysis of food stuff such as tomatoes is demonstrated which open the way to their use for monitoring of food contaminants by tailoring the aptamer.

show abstract

“…Figure a,b shows the optical image and schematic of the fabricated devices. Since the mobility varies little within the thickness of 8–12 layers, [ 24 ] 5–8 nm MoS 2 flake was chosen to fabricate the devices. The fabrication flow can be depicted as follows: An exfoliated multilayer MoS 2 flake (5–8 nm) was transferred on a 300 nm SiO 2 with heavily doped P ++ Si substrate, which served as the bottom gate for the devices.…”

Section: Methodsmentioning

confidence: 99%

Enhanced Electrical Performance of Van der Waals Heterostructure

Wang

Hsiao

et al. 2021

Adv Materials Inter

View full text Add to dashboard Cite

As opposed to the semimetal graphene, TMDs have shown great potential in the sub-5 nm regime applications due to their dangling bond-free surfaces, satisfied bandgaps, attractive electronic properties, powerful optoelectronic applications, and well mechanical properties. [3-6] MoS 2 is considered to be the most promising one from the family of layered TMDs due to their feasibility in large-scale synthesis. [7] Bulk MoS 2 is known to have an indirect bandgap of ≈1.2 eV, whereas single-layer MoS 2 is a direct gap semiconductor with a bandgap of 1.8 eV. [8-12] The direct bandgap also results in the photoluminescence (PL) of monolayer MoS 2 , which opens the possibility of many optoelectronic applications. [13] However, MoS 2 at both room temperatures (RT) and low temperatures have been found to be substantially below the theoretically predicted intrinsic values, which can be attributed to the scattering of carriers by substrate roughness, charged impurities, and the presence of adsorbates (H 2 O, gas, etc.) on the surface. [14-16] In addition, the high Rc values of the MoS 2 FETs limited their two-terminal field-effect mobility which may have been caused by the Schottky barrier at the interface of MoS 2 and metal. [17-21] In this regard, the Schottky barrier height (SBH) is an important parameter for examining contact properties. The low work function metal contact electrode and molecular doping interface are conventional ways, [22] which aim to reduce contact resistance; however, the charged impurities in ultra-sensitive MoS 2 channel make the methods less efficient in terms of mobility enhancement. Here, we propose a multiple TMDs materials such as the MoS 2 /WS 2 Van der Waals heterostructure FET. With the high electron affinity of MoS 2 , the free electrons in the WS 2 layers are transferred to the MoS 2 layers, resulting in the n-doping of the MoS 2. [23] Within this heterostructure, the electrons can transport through the Van der Waals self-encapsulated channel and easily overcome the barrier at the interface, which is due to the Schottky barrier lowering effect. With the absence of the scattering source, the carrier concentration increases without degrading the mobility of the MoS 2 heterostructure, thus, the ON current and mobility of the device can be significantly enhanced. Moreover, we demonstrated a double Van der Waals heterostructure device where the MoS 2 layer is encapsulated by two WS 2 layers. The combination of the two heterostructures could further boost the mobility at room temperature and achieve a much higher value at 30 K, indicating the suppression of the Coulomb scattering at the oxide of the MoS 2 interface. In this study, a novel van der Waals (vdW) heterostructure field-effect transistor (FET) using vdW stacking as next-generation device architecture is demonstrated. The MoS 2 /WS 2 heterostructure FET exhibits a large improvement in the drain current and field-effect mobility (from 43.3 to 62.4 cm 2 V −1 s −1) compared with single MoS 2 FET. Such significant enhancement is mainly due to...

show abstract

Thickness-Dependent Enhancement of Electronic Mobility of MoS₂ Transistors via Surface Functionalization

Cited by 18 publications

References 41 publications

Tailoring the Fluorescent and Electronic Properties of 2H-MoS₂ by Step-by-Step Functionalization

Tailoring the Fluorescent and Electronic Properties of 2H-MoS₂ by Step-by-Step Functionalization

Self-Assembled MoS2/ssDNA Nanostructures for the Capacitive Aptasensing of Acetamiprid Insecticide

Enhanced Electrical Performance of Van der Waals Heterostructure

Contact Info

Product

Resources

About

Thickness-Dependent Enhancement of Electronic Mobility of MoS2 Transistors via Surface Functionalization

Cited by 18 publications

References 41 publications

Tailoring the Fluorescent and Electronic Properties of 2H-MoS2 by Step-by-Step Functionalization

Tailoring the Fluorescent and Electronic Properties of 2H-MoS2 by Step-by-Step Functionalization

Self-Assembled MoS2/ssDNA Nanostructures for the Capacitive Aptasensing of Acetamiprid Insecticide

Enhanced Electrical Performance of Van der Waals Heterostructure

Contact Info

Product

Resources

About

Thickness-Dependent Enhancement of Electronic Mobility of MoS₂ Transistors via Surface Functionalization

Tailoring the Fluorescent and Electronic Properties of 2H-MoS₂ by Step-by-Step Functionalization

Tailoring the Fluorescent and Electronic Properties of 2H-MoS₂ by Step-by-Step Functionalization