Van der Waals integration before and beyond two-dimensional materials

Liu, Yuan; Huang, Yu; Duan, Xiangfeng

doi:10.1038/s41586-019-1013-x

Cited by 1,158 publications

(987 citation statements)

References 130 publications

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“…With the addition of Ti 3 C 2 T x nanosheet, the overall electrical conductivity increases when the loading fraction is not high, as shown in Figure 4a. [21] The carrier concentration of Ti 3 C 2 T x nanosheet (n s ) estimated by the rule of mixture [22] is 2.19 × 10 21 cm -3 for the 1 vol% composite, which is in the same order of reported value (8 × 10 21 cm -3 ) for pure Ti 3 C 2 T x [23] while two orders higher than that of bulk BST. The enhanced electrical conductivity can be attributed to the increased carrier concentration (n) derived from Ti 3 C 2 T x phase.…”

Section: Thermoelectric Transport Propertiesmentioning

confidence: 57%

High‐Efficiency Thermoelectric Power Generation Enabled by Homogeneous Incorporation of MXene in (Bi,Sb)₂Te₃ Matrix

Zhang

Liao

et al. 2019

Advanced Energy Materials

139

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received widespread attention during the past decades. It enables direct conversion between heat and electricity which has been used in space exploration, microelectronics, automobiles and so on. [1] However, the widespread application of thermoelectric devices in daily life is severely limited by the low thermoelectric conversion efficiency, which is mainly related to the dimensionless figure of merit ZT = α 2 σT/κ, where α, σ, and T are the Seebeck coefficient, electrical conductivity, absolute temperature, respectively and thermal conductivity κ is composed of electronic (κ e ) and lattice (κ l ) contributions. [2] Among the developed TE materials with high ZT (≥1), the V 2 VI 3 (V represents Group V elements Sb and Bi, and VI is Group VI elements S, Se and Te) compounds and derivatives have been intensively investigated for a long history since 1950s, which are widely considered as the benchmark of high performance TE materials in low-to mid-temperature range. [3] The outstanding TE performance of V 2 VI 3 materials represented by Sb 2 Te 3 , Bi 2 Te 3 , and Bi 2 Se 3 can be ascribed to its high power factor (PF) due to the suitable carrier concentration and low κ derived from the layered structure weakly bonded by van der Waals interaction. [3] Optimized by isoelectronic extrinsic doping, much improved TE performance with the maximum ZT around 1 has been The (Bi,Sb) 2 Te 3 (BST) compounds have long been considered as the benchmark of thermoelectric (TE) materials near room temperature especially for refrigeration. However, their unsatisfactory TE performances in wide-temperature range severely restrict the large-scale applications for power generation. Here, using a self-assembly protocol to deliver a homogeneous dispersion of 2D inclusion in matrix, the first evidence is shown that incorporation of MXene (Ti 3 C 2 T x ) into BST can simultaneously achieve the improved power factor and greatly reduced thermal conductivity. The oxygen-terminated Ti 3 C 2 T x with proper work function leads to highly increased electrical conductivity via hole injection and retained Seebeck coefficient due to the energy barrier scattering. Meanwhile, the alignment of Ti 3 C 2 T x with the layered structure significantly suppresses the phonon transport, resulting in higher interfacial thermal resistance. Accordingly, a peak ZT of up to 1.3 and an average ZT value of 1.23 from 300 to 475 K are realized for the 1 vol% Ti 3 C 2 T x /BST composite. Combined with the high-performance composite and rational device design, a record-high thermoelectric conversion efficiency of up to 7.8% is obtained under a temperature gradient of 237 K. These findings provide a robust and scalable protocol to incorporate MXene as a versatile 2D inclusion for improving the overall performance of TE materials toward high energy-conversion efficiency.

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Section: Thermoelectric Transport Propertiesmentioning

confidence: 57%

High‐Efficiency Thermoelectric Power Generation Enabled by Homogeneous Incorporation of MXene in (Bi,Sb)₂Te₃ Matrix

Zhang

Liao

et al. 2019

Advanced Energy Materials

139

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“…The separation and transportation of photogenerated carriers could be remarkably enhanced in the photodiode structures . Also, the unique properties of the 2D layered materials, including dangling‐bond‐free surface and capability to interact with another 2D layered material or non‐2D material through van der Waals (vdW) force, enable the creation of van der Waals heterostructures (vdWHs) without lattice distortion . In light of this, photodiodes based on various hybrid 2D–2D vdWHs, such as MoS 2 /WS 2 and graphene/WSe 2 /graphene, have been fabricated .…”

Section: Introductionmentioning

confidence: 99%

Ultrahigh Speed and Broadband Few‐Layer MoTe₂/Si 2D–3D Heterojunction‐Based Photodiodes Fabricated by Pulsed Laser Deposition

et al. 2020

Adv Funct Materials

147

115

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2D transition metal dichalcogenides are promising candidates for high‐performance photodetectors. However, the relatively low response speed as well as the complex transfer process hinders their wide applications. Herein, for the first time, the fabrication of a few‐layer MoTe2/Si 2D–3D vertical heterojunction for high‐speed and broadband photodiodes by a pulsed laser deposition technique is reported. Owing to the high junction quality, ultrathin MoTe2 film thickness, and unique vertical n–n heterojunction structure, the photodiode exhibits excellent device performance in terms of a high responsivity of 0.19 A W−1 and a large detectivity of 6.8 × 1013 Jones. The device is also capable of detecting a broadband light with wavelength spanning from 300 to 1800 nm. More importantly, the device possesses an ultrahigh response speed up to 150 ns with a 3‐dB electrical bandwidth approaching 0.12 GHz. This work paves the way toward the fabrication of novel 2D–3D heterojunctions for high‐performance, ultrafast photodetectors.

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“…Gate-tunable physical properties enable these atomically-thin layered materials [32] to be promising in the design of diverse electronic and optoelectronic devices. [42][43][44][45] The unique properties that 2D materials and vdW heterostructures exhibit may be utilized to solve the aforementioned issues faced by conventional memristive devices. [42][43][44][45] The unique properties that 2D materials and vdW heterostructures exhibit may be utilized to solve the aforementioned issues faced by conventional memristive devices.…”

Section: Introductionmentioning

confidence: 99%

2D Layered Materials for Memristive and Neuromorphic Applications

Wang

Meng

et al. 2019

Adv Elect Materials

101

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demonstrated that the memristive devices exhibit many promising features, [3][4][5][6][7][8] such as non-volatility, high speed switching, high endurance, high-density integration, CMOS-compatible fabrication, and so on. These features make them ideal candidates for applications in memory devices, [3,5,9] in-memory computing, [3,[10][11][12] and edge computing. [13,14] The working principle of the TMOs-based memristive devices relies on ion drift or diffusion, which resembles motion of ions in the biological neurons and synapses. The ionic motions exhibit dynamic behaviors. Thus, the memristive devices can be used to emulate the synaptic plasticity [15] and neurons. [16][17][18] Compared to traditional silicon synapses [19][20][21] and neurons [22,23] requiring complex circuits, such emerging memristive devices have compact structures and enhanced func-

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Van der Waals integration before and beyond two-dimensional materials

Cited by 1,158 publications

References 130 publications

High‐Efficiency Thermoelectric Power Generation Enabled by Homogeneous Incorporation of MXene in (Bi,Sb)₂Te₃ Matrix

High‐Efficiency Thermoelectric Power Generation Enabled by Homogeneous Incorporation of MXene in (Bi,Sb)₂Te₃ Matrix

Ultrahigh Speed and Broadband Few‐Layer MoTe₂/Si 2D–3D Heterojunction‐Based Photodiodes Fabricated by Pulsed Laser Deposition

2D Layered Materials for Memristive and Neuromorphic Applications

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Van der Waals integration before and beyond two-dimensional materials

Cited by 1,158 publications

References 130 publications

High‐Efficiency Thermoelectric Power Generation Enabled by Homogeneous Incorporation of MXene in (Bi,Sb)2Te3 Matrix

High‐Efficiency Thermoelectric Power Generation Enabled by Homogeneous Incorporation of MXene in (Bi,Sb)2Te3 Matrix

Ultrahigh Speed and Broadband Few‐Layer MoTe2/Si 2D–3D Heterojunction‐Based Photodiodes Fabricated by Pulsed Laser Deposition

2D Layered Materials for Memristive and Neuromorphic Applications

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Product

Resources

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High‐Efficiency Thermoelectric Power Generation Enabled by Homogeneous Incorporation of MXene in (Bi,Sb)₂Te₃ Matrix

High‐Efficiency Thermoelectric Power Generation Enabled by Homogeneous Incorporation of MXene in (Bi,Sb)₂Te₃ Matrix

Ultrahigh Speed and Broadband Few‐Layer MoTe₂/Si 2D–3D Heterojunction‐Based Photodiodes Fabricated by Pulsed Laser Deposition