Wafer-scale production of patterned transition metal ditelluride layers for two-dimensional metal–semiconductor contacts at the Schottky–Mott limit

Song, Seunguk; Sim, Yeoseon; Kim, Se‐Yang; Kim, Jung Hwa; Oh, Inseon; Na, Woongki; Lee, Do Hee; Wang, Jaewon; Yan, Shili; Liu, Yinan; Kwak, Jinsung; Chen, Jianhao; Cheong, Hyeonsik; Yoo, Jae Cheal; Lee, Zonghoon; Kwon, Soon‐Yong

doi:10.1038/s41928-020-0396-x

Cited by 122 publications

(81 citation statements)

References 56 publications

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“…This is likely due to the growth occurring at a solid-liquid interface, rather than the typical solid-vapour one. Having the liquid Te in direct contact with the W layer counteracts the low activity of Te and facilitates the synthesis of WTe 2 at the comparatively low synthesis temperature and short time, which is similar to other works using Ni x Te y alloys [45]. Furthermore, H 2 is not required, unlike previously reported methods [46].…”

Section: Synthesis Of Wte 2 Filmssupporting

confidence: 62%

Synthesis of tungsten ditelluride thin films and highly crystalline nanobelts from pre-deposited reactants

et al. 2020

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Tungsten ditelluride (WTe 2) is a layered transition metal dichalcogenide (TMD) that has attracted increasing research interest in recent years. WTe 2 has demonstrated large non-saturating magnetoresistance, potential for spintronic applications and promise as a type-II Weyl semimetal. The majority of works on WTe 2 have relied on mechanically exfoliated flakes from chemical vapour transport (CVT)-grown crystals for their investigations. While producing high-quality samples, this method is hindered by several disadvantages including long synthesis time, high-temperature annealing and an inherent lack of scalability. In this work, a synthesis method is demonstrated that allows the production of large-area polycrystalline films of WTe 2. This is achieved by the reaction of pre-deposited films of W and Te at a relatively low temperature of 550 °C. Sputter X-ray photoelectron spectroscopy reveals the rapid but self-limiting nature of the oxidation of these WTe 2 films in ambient conditions. The WTe 2 films are composed of areas of micrometre-sized nanobelts that can be isolated and offer potential as an alternative to CVT-grown samples. These nanobelts are highly crystalline with low defect densities indicated by transmission electron microscopy and show promising initial electrical results.

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Section: Synthesis Of Wte 2 Filmssupporting

confidence: 62%

Synthesis of tungsten ditelluride thin films and highly crystalline nanobelts from pre-deposited reactants

et al. 2020

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“…The fundamental reason for causing the opposite result is that unlike 3D metal Pd, the 2D metal 1T′-MoTe 2 can suppress the strong Fermi pinning effect at the metal-semiconductor interface. In reality, the Schottky barrier heights between most 3D metals and monolayer MoS 2 had seriously deviated from the Schottky-Mott rule 22,24 , resulting in the significantly lower Schottky barrier of 0-0.3 eV than the theoretical values in Fig. 2e.…”

Section: Resultsmentioning

confidence: 82%

“…Both achieving the designed Schottky barrier height and precisely controlling the barrier width are crucial for realizing the full potential of Schottky diodes. For Schottky barrier height, transferring metals or employing 2D metals can build weak Fermi pinned Schottky junctions to roughly satisfy the personalized barrier height 2,[21][22][23] . The 2D metals (e.g., 1T′-MoTe 2 , 1T′-WTe 2 , 1T′-PtSe 2 , and 2H-NbSe 2 ), by contrast, have more potential in creating high-grade Schottky junctions because their Schottky barrier heights strictly follow the trend of the Schottky-Mott model.…”

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confidence: 99%

Near-ideal van der Waals rectifiers based on all-two-dimensional Schottky junctions

et al. 2021

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The applications of any two-dimensional (2D) semiconductor devices cannot bypass the control of metal-semiconductor interfaces, which can be severely affected by complex Fermi pinning effects and defect states. Here, we report a near-ideal rectifier in the all-2D Schottky junctions composed of the 2D metal 1 T′-MoTe2 and the semiconducting monolayer MoS2. We show that the van der Waals integration of the two 2D materials can efficiently address the severe Fermi pinning effect generated by conventional metals, leading to increased Schottky barrier height. Furthermore, by healing original atom-vacancies and reducing the intrinsic defect doping in MoS2, the Schottky barrier width can be effectively enlarged by 59%. The 1 T′-MoTe2/healed-MoS2 rectifier exhibits a near-unity ideality factor of ~1.6, a rectifying ratio of >5 × 105, and high external quantum efficiency exceeding 20%. Finally, we generalize the barrier optimization strategy to other Schottky junctions, defining an alternative solution to enhance the performance of 2D-material-based electronic devices.

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“…Secondly, in the aspect of practical applications in (opto)electronics, the contact effect between metal and semiconductor is an undeniable problem, which plays a deterministic role in devices based on wafer-scale vdWHs. 186,187 Despite the enhanced carriers transport in vdWHs channels, 148,188 many (opto)electronic devices still show low mobility due to the high contact resistance and Schottky barrier height (SBH). 189,190 The poor contact between vdWHs and metal electrodes is the result of profound Fermi pining effect and uneven contact interface in a large area.…”

Section: Discussionmentioning

confidence: 99%

“…191,192 Hence, modifying the metalsemiconductor contact interface is an effective strategy to improve device performance. Specifically, using metallic 2D materials (graphene, 193 some 1 T phase TMDs 47,187,[194][195][196][197] ) as electrodes for (opto)electronics through epitaxy growth 35 or phase transition 198,199 will alleviate the pining effect. In addition, transferring the prefabricated metal electrodes can also avoid creating defects and strains, resulting in an atomically sharp and near perfect metal/2D semiconductor interface.…”

Section: Discussionmentioning

confidence: 99%

Wafer‐scale vertical van der Waals heterostructures

Liu

Zhai

2020

InfoMat

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Wafer‐scale van der Waals heterostructures (vdWHs), benefitting from the rich diversity in materials available and stacking geometry, precise controllability in devices structure and performance, and unprecedented potential in practical application, have attracted considerable attention in the field of two‐dimensional (2D) materials. This article reviews the state‐of‐the‐art research activities that focus on wafer‐scale vdWHs and their (opto)electronic applications. We begin with the preparation strategies of vdWHs with wafer size and illustrate them from four key aspects, that is, mechanical‐assembly stack, successive deposition, synchronous evolution, and seeded growth. We discuss the fundamental principle, underlying mechanism, advantages, and disadvantages for each strategy. We will then review the applications of large‐area vdWHs based devices in electronic, optoelectronic and flexible devices field, unveiling their promising potential for practical application. Ultimately, we will demonstrate the challenges they face and provide some viable solutions on wafer‐scale heterostructure synthesis and device fabrication.

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Wafer-scale production of patterned transition metal ditelluride layers for two-dimensional metal–semiconductor contacts at the Schottky–Mott limit

Cited by 122 publications

References 56 publications

Synthesis of tungsten ditelluride thin films and highly crystalline nanobelts from pre-deposited reactants

Synthesis of tungsten ditelluride thin films and highly crystalline nanobelts from pre-deposited reactants

Near-ideal van der Waals rectifiers based on all-two-dimensional Schottky junctions

Wafer‐scale vertical van der Waals heterostructures

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