Preparation Engineering of Two-Dimensional Heterostructures <i>via</i> Bottom-Up Growth for Device Applications

Zhou, Xuebing; Yu, Gui

doi:10.1021/acsnano.1c02985

Cited by 28 publications

(23 citation statements)

References 136 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Compared with the WSe 2 FET on a SiO 2 /Si substrate, the direct CVD-grown WSe 2 /h-BN vdWH-based FETs exhibited improved carrier mobility, which is attributed to the decrease in interfacial trapping states and substrate scattering effects. [171] A transverse comparison of different FETs based on MoS 2 gown on exfoliated and as-grown wafer-scale h-BN exhibited a similar performance improvement effect (Figure 11f), [40] further highlighting the advantages of using h-BN and CVD-grown methods.…”

Section: Vdwhs and Vdwsls For Electronic Devicesmentioning

confidence: 89%

Controllable Preparation of 2D Vertical van der Waals Heterostructures and Superlattices for Functional Applications

Liang

Yang

et al. 2022

Small

View full text Add to dashboard Cite

In general, 2D materials adopt a unique layered crystal structure, i.e., the neighboring layers are bonded together by weak van der Waals (vdW) interactions and the intralayer atoms and are bonded together through strong covalent or ionic bonds, which allows easy exfoliation of atomically thin nanosheets from their bulk counterpart. With a surface free of dangling bonds surface, 2D vdW materials can be integrated to produce next-generation vdW heterostructures (vdWHs) or vdW superlattices (vdWSLs), which provide a powerful material platform for exploring fundamentally new physics and exotic devices. For conventionally bonded heterostructures, the synthesis relies heavily on one-to-one chemical bonds, and the component materials must satisfy strict lattice matching and processing compatibility requirements. [3] It is difficult for the bonded heterostructures/superlattices between materials with mismatched lattices to maintain the intrinsic heterogeneous interface, resulting in various types of damage, such as strain, defects, atomic exchange, and distortion. [4,5] However, vdW integration can overcome the limits of bonded heterostructures, allowing unprecedented flexibility to combine materials with radically different chemical compositions, crystal structures, or electronic properties. [6][7][8] More importantly, the as-fabricated vdWHs possess atomically sharp and clean vdW interfaces along with well-defined moiré superlattices, enabling a series of unique electronic and photonic characteristics that cannot be realized in conventionally bonded heterostructures, such as ultrahigh on-current and mobility in 2D metal-semiconductor (M-S) vdWH-based field-effect transistors (FETs), [7,9] interlayer coupling and ultrafast charge transfer in transition-metal dichalcogenide (TMD) heterostructures, [10] Mott-like insulator and superconducting behavior in magic-angled graphene, [11,12] moiré excitons in twisted TMD heterobilayers, [13,14] and topological superconductivity in CrBr 3 /NbSe 2 ferromagnetic/superconductor vdWHs. [15] Therefore, developing reliable assembly methods for vdWHs or vdWSLs with atomically clean interfaces is an essential prerequisite for relevant physical exploration and practical applications.In general, the preparation methods for vdWHs or vdWSLs can be divided into top-down and bottom-up methods. To 2D van der Waals heterostructures (vdWHs) and superlattices (SLs) with exotic physical properties and applications for new devices have attracted immense interest. Compared to conventionally bonded heterostructures, the danglingbond-free surface of 2D layered materials allows for the feasible integration of various materials to produce vdWHs without the requirements of lattice matching and processing compatibility. The quality of interfaces in artificially stacked vdWHs/vdWSLs and scalability of production remain among the major challenges in the field of 2D materials. Fortunately, bottom-up methods exhibit relatively high controllability and flexibility. The growth parameters, such as the temperatur...

show abstract

Section: Vdwhs and Vdwsls For Electronic Devicesmentioning

confidence: 89%

Controllable Preparation of 2D Vertical van der Waals Heterostructures and Superlattices for Functional Applications

Liang

Yang

et al. 2022

Small

View full text Add to dashboard Cite

show abstract

“…As compared with the growth of vertical heterostructures, the growth of lateral heterostructures is more critical for the fabrication method and the selection of components. Commonly, the CVD method is more suitable for the preparation of lateral heterostructures than mechanical transfer as well as solution synthesis due to the covalent nature of bonds at the junction interface. The lateral heterostructures requires constituents with similar crystal structures and a small lattice mismatch between them. − For example, layered topological insulators (TI), such as Bi 2 Te 3 , Bi 2 Se 3 , and Sb 2 Te 3 , share a similar anisotropic bonding nature as well as similar lattice constants.…”

Section: Cvd Growth Of 2d Heterostructuresmentioning

confidence: 99%

Controlled Growth of Two-Dimensional Heterostructures: In-Plane Epitaxy or Vertical Stack

et al. 2022

View full text Add to dashboard Cite

Conspectus Two-dimensional (2D) heterostructures have created many novel properties and triggered a variety of promising applications, thus setting off a boom in the modern semiconductor industry. As the first road to step into adequately exploring the properties and real applications, the material preparation process matters a lot. Adhering to the concept of epitaxial growth, chemical vapor deposition (CVD) shows great potential for the preparation of heterostructures for commercialization. At this stage, the growth of 2D heterostructures through CVD methods is still in its infancy in spite of the fact that a great number of 2D heterostructures have been obtained via the CVD process. In order to maximize the excellent properties of 2D heterostructures as well as the compatibility with device engineering, a great deal of effort has been devoted to the CVD growth process of 2D heterostructures with large domain size, high-quality features, and high stability. However, most heterostructures still suffer from the problems of thermally induced degradation, ill-controllable growth directions, and limited material combinations, which will further affect device performance. The main reason is that there is a lack of in-depth understanding of the underlying growth mechanisms, which is of great significance for the development of state-of-the-art optoelectronic devices. In this Account, we first discuss the fundamental mechanisms of the controlled growth of 2D heterostructures to realize in-plane epitaxy or the vertical stack during CVD growth. Two key parameters should be considered during the growth process: growth kinetics and thermodynamics. Then we present the natural heteroepitaxy behaviors between different material systems. Generically, components with similar crystal structures tend to form lateral heterostructures, while for components with different crystal structures, vertical heterostructures are more favorable. Several approaches to the engineering of growth directions and nucleation sites of 2D heterostructures are presented, which provide both theoretical and experimental guidance for the controllable growth of 2D heterostructures with desired structures. Finally, potential opportunities are summarized concerning future developments in this emerging field, including (1) methods for the large-area production of 2D heterostructures, (2) the fabrication of high-quality semiconductor heterojunction arrays, (3) the exploration of novel 2D heterostructures, (4) precious control of the twist angles between the components in vertical heterostructures, and (5) the fabrication of vertical multilayer heterostructures. We believe this review can point the way to the controllable growth of various 2D heterostructures for exploring novel physics and provide a scalable pathway to high-performance devices.

show abstract

“…Semiconducting transition-metal dichalcogenides (s-TMDs), such as MoS 2 , WS 2 , MoSe 2 , and WSe 2 , have attracted tremendous attention owing to their excellent electrical and optical properties. − Vertical and lateral s-TMD heterostructures have been created in atomically thin devices to explore new electronic and photonic properties based on band structure engineering. − The heterostructures are commonly constructed by vertically stacking exfoliated (s-TMD) layers using mechanical transfer techniques, which have the problems of uncontrolled stacking angle, interfacial contamination, and low mass production . Recently, the chemical vapor deposition (CVD) method has been found to be effective for the synthesis of lateral TMD heterostructures with large-scale production and clean interfaces.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of a Selectively Nb-Doped WS₂–MoS₂ Lateral Heterostructure for a High-Detectivity PN Photodiode

Phan

et al. 2022

ACS Nano

View full text Add to dashboard Cite

In this study, selective Nb doping (P-type) at the WS 2 layer in a WS 2 −MoS 2 lateral heterostructure via a chemical vapor deposition (CVD) method using a solution-phase precursor containing W, Mo, and Nb atoms is proposed. The different chemical activity reactivity (MoO 3 > WO 3 > Nb 2 O 5 ) enable the separation of the growth temperature of intrinsic MoS 2 to 700 °C (first grown inner layer) and Nb-doped WS 2 to 800 °C (second grown outer layer). By controlling the Nb/(W+Nb) molar ratio in the solution precursor, the hole carrier density in the p-type WS 2 layer is selectively controlled from approximately 1.87 × 10 7 /cm 2 at 1.5 at.% Nb to approximately 1.16 × 10 13 / cm 2 at 8.1 at.% Nb, while the electron carrier density in n-type MoS 2 shows negligible change with variation of the Nb molar ratio. As a result, the electrical behavior of the WS 2 −MoS 2 heterostructure transforms from the N−N junction (0 at.% Nb) to the P−N junction (4.5 at.% Nb) and the P−N tunnel junction (8.1 at.% Nb). The band-toband tunneling at the P−N tunnel junction (8.1 at.% Nb) is eliminated by applying negative gate bias, resulting in a maximum rectification ratio (10 5 ) and a minimum channel resistance (10 8 Ω). With this optimized photodiode (8.1 at.% Nb at V g = −30 V), an I photo /I dark ratio of 6000 and a detectivity of 1.1 × 10 14 Jones are achieved, which are approximately 20 and 3 times higher, respectively, than the previously reported highest values for CVD-grown transition-metal dichalcogenide P−N junctions.

show abstract

Preparation Engineering of Two-Dimensional Heterostructures via Bottom-Up Growth for Device Applications

Cited by 28 publications

References 136 publications

Controllable Preparation of 2D Vertical van der Waals Heterostructures and Superlattices for Functional Applications

Controllable Preparation of 2D Vertical van der Waals Heterostructures and Superlattices for Functional Applications

Controlled Growth of Two-Dimensional Heterostructures: In-Plane Epitaxy or Vertical Stack

Synthesis of a Selectively Nb-Doped WS₂–MoS₂ Lateral Heterostructure for a High-Detectivity PN Photodiode

Contact Info

Product

Resources

About

Preparation Engineering of Two-Dimensional Heterostructures via Bottom-Up Growth for Device Applications

Cited by 28 publications

References 136 publications

Controllable Preparation of 2D Vertical van der Waals Heterostructures and Superlattices for Functional Applications

Controllable Preparation of 2D Vertical van der Waals Heterostructures and Superlattices for Functional Applications

Controlled Growth of Two-Dimensional Heterostructures: In-Plane Epitaxy or Vertical Stack

Synthesis of a Selectively Nb-Doped WS2–MoS2 Lateral Heterostructure for a High-Detectivity PN Photodiode

Contact Info

Product

Resources

About

Synthesis of a Selectively Nb-Doped WS₂–MoS₂ Lateral Heterostructure for a High-Detectivity PN Photodiode