Planar heterostructures of single-layer transition metal dichalcogenides: Composite structures, Schottky junctions, tunneling barriers, and half metals

Aras, Mehmet; Kılıç, Çetin; Çiraci, S.

doi:10.1103/physrevb.95.075434

Cited by 26 publications

(32 citation statements)

References 48 publications

(50 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this respect, the stability of bilayers and multilayer stacks is also enhanced. Recent theoretical stability analysis 29,35 and extensive structure optimization calculations carried out here as well as recent experimental studies 7,27,28,33,36−38 indicate that the vertical and lateral heterostructures treated in the present study are stable and can be fabricated. It should also be pointed out that lateral homojunctions combining hexagonal (semiconducting) and monoclinic (metallic) phases of MoTe 2 have already been fabricated via laser-induced phase patterning.…”

Section: ■ Introductionsupporting

confidence: 61%

“…The electronic structure of 2D SL MoTe 2 and NiTe 2 as well as the energetics and thermal stability of zigzag or armchair edged lateral heterostructures were discussed in our previous study. 29 In the present study we consider features which were not treated earlier. Moreover, we contrast these features with those of the vertical heterostructures.…”

Section: ■ Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Lateral and Vertical Heterostructures of Transition Metal Dichalcogenides

2018

Self Cite

View full text Add to dashboard Cite

In this paper we investigate periodic lateral and vertical heterostructures of transition metal dichalcogenides (TMDs). Lateral heterostructures are constructed by the alternating metallic and semiconducting single-layer stripes of TMDs joined commensurately along their armchair edges and attain different states depending on the widths of constituents. While these heterostructures acquire a composite character with metallic state for narrow stripes, large stripes lead to the confinement of electronic states and function as metal− semiconductor junctions with a tunable Schottky barrier. The interface or boundary between constituent stripes has finite extension and allows charge transfer between them. On the other hand, the weak van der Waals interaction between layers sets the features of vertical heterostructures. Their interfaces are sharp: metal−semiconductor junction and Schottky barrier developed thereof can be induced even within a few layers. In the absence of dopants, we find minute charge transfer across the interface with negligible band bending in vertical heterostructures. The δ-doping of the semiconducting constituent by the metallic one forms strictly two-dimensional metallic electrons in a three-dimensional layered semiconductor and leads to crucial directionality effects and quantization of conductance. Our work unveils significant differences between lateral and vertical heterostructures.

show abstract

Section: ■ Introductionsupporting

confidence: 61%

Section: ■ Resultsmentioning

confidence: 99%

Lateral and Vertical Heterostructures of Transition Metal Dichalcogenides

2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…[134][135][136] Composite structures made of lateral and vertical junctions of 2D SL structures like Graphene/BN or MoS 2 / WS 2 that have been previously treated both theoretically and experimentally, heralded great potential for new generation artificial structures with promising applications. 20,[137][138][139][140][141] Motivated with the synthesis of very thin h-GaN and h-AlN, Onen et al 35 recently studied the composite structures of their single-layers. They showed that stable, in-plane composite materials, (GaN) p /(AlN) q can be constructed of periodically repeating stripes of GaN and AlN continuously (or commensurately) joined along their zigzag (Z) edges.…”

Section: Composite Structures Of Gan/alnmentioning

confidence: 99%

Fundamentals, progress, and future directions of nitride-based semiconductors and their composites in two-dimensional limit: A first-principles perspective to recent synthesis

Kecik

Önen

Konuk

et al. 2018

Applied Physics Reviews

Self Cite

View full text Add to dashboard Cite

Potential applications of bulk GaN and AlN crystals have made possible single and multilayer allotropes of these III-V compounds to be a focus of interest recently. As of 2005, the theoretical studies have predicted that GaN and AlN can form two-dimensional (2D) stable, single-layer (SL) structures being wide band gap semiconductors and showing electronic and optical properties different from those of their bulk parents. Research on these 2D structures have gained importance with recent experimental studies achieving the growth of ultrathin 2D GaN and AlN on substrates. It is expected that these two materials will open an active field of research like graphene, silicene, and transition metal dichalcogenides. This topical review aims at the evaluation of previous experimental and theoretical works until 2018 in order to provide input for further research attempts in this field. To this end, starting from three-dimensional (3D) GaN and AlN crystals, we review 2D SL and multilayer (ML) structures, which were predicted to be stable in free-standing states. These are planar hexagonal (or honeycomb), tetragonal, and square-octagon structures. First, we discuss earlier results on dynamical and thermal stability of these SL structures, as well as the predicted mechanical properties. Next, their electronic and optical properties with and without the effect of strain are reviewed and compared with those of the 3D parent crystals. The formation of multilayers, hence prediction of new periodic layered structures and also tuning their physical properties with the number of layers are other critical subjects that have been actively studied and discussed here. In particular, an extensive analysis pertaining to the nature of perpendicular interlayer bonds causing planar GaN and AlN to buckle is presented. In view of the fact that SL GaN and AlN can be fabricated only on a substrate, the question of how the properties of free-standing, SL structures are affected if they are grown on a substrate is addressed. We also examine recent works treating the composite structures of GaN and AlN joined commensurately along their zigzag and armchair edges and forming heterostructures, d-doping, single, and multiple quantum wells, as well as core/ shell structures. Finally, outlooks and possible new research directions are briefly discussed. Published by AIP Publishing. https://doi.

show abstract

“…The Schottky-Barrier height plays an important role in the transport properties of of SBFETs. Recent theoretical study demonstrates the linear bending of the band edges of the semiconductor at the boundary between the metal and semiconductor will affect the Schottky-Barrier height effectively [35]. Following their method, we calculate the Schottky-Barrier height of our devices from the local density states (LDOS), the transmission spectrum and the averaged potential along Z direction in Fig.…”

Section: Model and Simulation Approachmentioning

confidence: 99%

In-plane Schottky-barrier field-effect transistors based on 1 T /2 H heterojunctions of transition-metal dichalcogenides

et al. 2017

View full text Add to dashboard Cite

As Moore's law approaches its end, two dimensional (2D) materials are intensely studied for their potentials as one of the "More than Moore' (MM) devices. However, the ultimate performance limits and the optimal design parameters for such devices are still unknown. One common problem for the 2D material based device is the relative weak on-current. In this study, two dimensional Schottky-Barrier Field-Effect Transistors (SBFETs) consisted with in-plane hetero-junctions of 1T metallic-phase and 2H semiconducting-phase Transition-Metal Dichalcogenide (TMD) are studied following the recent experimental synthesis of such devices at much larger scale. Our ab initio simulation reveals the ultimate performance limits of such devices, and offers suggestions for better TMD materials. Our study shows that the Schottky-Barrier heights (SBH) of the in-plane 1T/2H contacts are smaller than the SBH of out-of-plane contacts, and the contact coupling is also stronger in the in-plane contact. Due to the atomic thickness of the mono-layer TMD, the average subthreshold swing (SS) of the in-plane TMD-SBFETs are found to be close to the limit of 60mV/dec, and smaller than that of out-of-plane TMD-SBFET device. Different TMDs are considered, and it is found that the in-plane WTe 2-SBFET provides the best performance, and it can satisfy the performance requirement of sub-10nm high performance (HP) Transistor outlined by International Technology Roadmap for Semiconductors (ITRS), thus could be developed into a viable sub-10nm MM device in the future.

show abstract

Planar heterostructures of single-layer transition metal dichalcogenides: Composite structures, Schottky junctions, tunneling barriers, and half metals

Cited by 26 publications

References 48 publications

Lateral and Vertical Heterostructures of Transition Metal Dichalcogenides

Lateral and Vertical Heterostructures of Transition Metal Dichalcogenides

Fundamentals, progress, and future directions of nitride-based semiconductors and their composites in two-dimensional limit: A first-principles perspective to recent synthesis

In-plane Schottky-barrier field-effect transistors based on 1 T /2 H heterojunctions of transition-metal dichalcogenides

Contact Info

Product

Resources

About