Semiconducting Properties of Single Crystals of <i>n</i>- and <i>p</i>-Type Tungsten Diselenide (WSe2)

Upadhyayula, L.C.; Loferski, J. J.; Wold, A.; Giriat, W.; Kershaw, R.

doi:10.1063/1.1655829

Cited by 102 publications

(34 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Additional evidence for hole localization is provided by the observed energy shift of the core levels of about 0.5 eV (see Fig. above), which is smaller than half of the band gap E g of WSe 2 (E g = 1.35 eV ), i.e., starting from a mid gap position of the Fermi level E F for undoped WSe 2 , this would indicate a pinning of E F above the valence band edge.…”

Section: Resultsmentioning

confidence: 88%

Surface functionalization of WSe₂ by F₁₆CoPc

Rückerl

Klaproth

Schuster

et al. 2016

Physica Status Solidi (b)

View full text Add to dashboard Cite

We have investigated the electronic properties of WSe2 surfaces covered by fluorinated cobalt phthalocyanine (F16CoPc) using photoemission spectroscopy. We show that a charge transfer occurs at this interface, which results in the creation of holes in the WSe2 surface while the Co center of the phthalocyanine is reduced to Co(I). We observe a potential change in WSe2 approaching the surface as a consequence of the induced positive charges near the surface. In addition, our data allow for a rough estimation of the induced charge density and suggest that the holes might be localized.

show abstract

Section: Resultsmentioning

confidence: 88%

Surface functionalization of WSe₂ by F₁₆CoPc

Rückerl

Klaproth

Schuster

et al. 2016

Physica Status Solidi (b)

View full text Add to dashboard Cite

show abstract

“…Similarly, the 3L WSe 2 FET also showed the p‐type doping characteristic with a higher current On/Off ratio of 400 (Figure S7D in SI). Since there are two kinds of WSe 2 single crystals, i.e., p‐type and n‐type, depending on the synthesis procedure,28, 56, 57 our electric results of WSe 2 FETs indicate that the p‐type single crystal of WSe 2 was used in this study.…”

Section: Resultsmentioning

confidence: 92%

Mechanical Exfoliation and Characterization of Single‐ and Few‐Layer Nanosheets of WSe₂, TaS₂, and TaSe₂

Li¹,

Lü²,

Wang³

et al. 2012

Small

593

441

View full text Add to dashboard Cite

Single- and few-layer transition-metal dichalcogenide nanosheets, such as WSe₂ , TaS₂, and TaSe₂, are prepared by mechanical exfoliation. A Raman microscope is employed to characterize the single-layer (1L) to quinary-layer (5L) WSe₂ nanosheets and WSe₂ single crystals with a laser excitation power ranging from 20 μW to 5.1 mW. Typical first-order together with some second-order and combinational Raman modes are observed. A new peak at around 308 cm⁻¹ is observed in WSe₂ except for the 1L WSe₂, which might arise from interlayer interactions. Red shifting of the A(1g) mode and the Raman peak around 308 cm⁻¹ is observed from 1L to 5L WSe₂. Interestingly, hexagonal- and monoclinic-structured WO₃ thin films are obtained during the local oxidation of thinner (1L-3L) and thicker (4L and 5L) WSe₂ nanosheets, while laser-burned holes are found during the local oxidation of the WSe₂ single crystal. In addition, the characterization of TaS₂ and TaSe₂ thin layers is also conducted.

show abstract

“…From this point of view, source materials and the mineralizer can be regarded as the most decisive factors in the growth of TMD crystals. Thereafter, the reaction conditions could be optimized case by case, typically in an empirical way, and some representative reactions are summarized in Table 1 …”

Section: Cvt Based Synthesis Of 2d Transition Metal Dichalcogenidesmentioning

confidence: 99%

“…Source materials and mineralizer are the decisive factors in CVT based synthesis of TMD crystal, and thus modulating the two factors can tune the features of resulting bulk TMD crystals. For example, for the synthesis of semiconducting WSe 2 , it was found that the mineralizer of Br 2 , SeCl 4 , or TeCl 4 selectively favors the formation of n‐type WSe 2 , while the mineralizer of I 2 yields its p‐type counterpart . In addition to the change of mineralizer, varying the ratio of source materials and the mineralizer is also a way to influence the features of the as‐synthesized TMD materials.…”

Section: Cvt Based Synthesis Of 2d Transition Metal Dichalcogenidesmentioning

confidence: 99%

Chemical Vapor Transport Reactions for Synthesizing Layered Materials and Their 2D Counterparts

Wang

Luo

Lü

et al. 2019

Small

View full text Add to dashboard Cite

semimetals (Si and Ge) to transition metal dichalcogenides (TMDs), which can be tuned from semiconductors to superconductors, have been intensively investigated. [8] Despite the recent advances in 2D materials, it is still challenging to obtain 2D materials with desired layers and size in facile and controllable manners.Indeed, continuous research has been carried out on the synthesis of 2D materials. [9] Generally, two synthetic strategies, known as top-down and bottom-up, are applied to obtain 2D materials. In the common top-down strategy, 2D materials are exfoliated from their bulk counterparts. Differently, using the bottom-up strategy, 2D materials with a few thin layers, even an atomically thin layer, can be directly synthesized from small building blocks such as molecules and atoms. [10] In these synthetic strategies for 2D materials, chemical vapor transport (CVT) reaction, an old yet powerful technology, plays an important role because CVT reactions can be used for both topdown and bottom-up syntheses of 2D materials. [11] CVT reactions represent a category of reactions with one common feature: a condensed phase, typically a solid, sublimes in the presence of a gaseous reactant (the mineralizer), and then deposits elsewhere usually in the form of crystals. [12] Notably, CVT is different from chemical vapor deposition (CVD), another chemical vapor-based approach for synthesizing 2D materials. Specifically, the main difference between CVT and CVD lies in the source materials for synthesizing products, where solid reactants are typically used in CVT and gaseous precursors are usually applied in CVD. The difference induces consequent differences in reactor design, operational control, and product features, thus bringing strengths and drawbacks for each approach. Since the discovery of CVT reaction by Bunsen in 1851, comprehensive understanding of CVT reactions in both experimental exploration and theoretical modeling has been established. [13] Furthermore, thousands of CVT reactions have been applied till now, producing a great variety of pure and crystalline solids, including metals, metalloids, intermetallic phases, metal oxides, halides, chalcogen halides, chalcogenides, and pnictides. [13,14] The knowledge about CVT reactions, together with the large number of applicable reactions, can offer opportunities for the controllable synthesis of 2D materials and the exploration of new 2D materials. Unfortunately, for the preparation of 2D materials, in stark contrast to the wide application of CVD, 2D materials, namely thin layers of layered materials, are attracting much attention because of their unique electronic, optical, thermal, and catalytic properties for wide applications. To advance both the fundamental studies and further practical applications, the scalable and controlled synthesis of large-sized 2D materials is desired, while there still lacks ideal approaches. Alternatively, the chemical vapor transport reaction is an old but powerful technique, and is recently adopted for synthesizing 2D material...

show abstract

Semiconducting Properties of Single Crystals of n- and p-Type Tungsten Diselenide (WSe2)

Cited by 102 publications

References 4 publications

Surface functionalization of WSe₂ by F₁₆CoPc

Surface functionalization of WSe₂ by F₁₆CoPc

Mechanical Exfoliation and Characterization of Single‐ and Few‐Layer Nanosheets of WSe₂, TaS₂, and TaSe₂

Chemical Vapor Transport Reactions for Synthesizing Layered Materials and Their 2D Counterparts

Contact Info

Product

Resources

About

Semiconducting Properties of Single Crystals of n- and p-Type Tungsten Diselenide (WSe2)

Cited by 102 publications

References 4 publications

Surface functionalization of WSe2 by F16CoPc

Surface functionalization of WSe2 by F16CoPc

Mechanical Exfoliation and Characterization of Single‐ and Few‐Layer Nanosheets of WSe2, TaS2, and TaSe2

Chemical Vapor Transport Reactions for Synthesizing Layered Materials and Their 2D Counterparts

Contact Info

Product

Resources

About

Surface functionalization of WSe₂ by F₁₆CoPc

Surface functionalization of WSe₂ by F₁₆CoPc

Mechanical Exfoliation and Characterization of Single‐ and Few‐Layer Nanosheets of WSe₂, TaS₂, and TaSe₂