2D Group IVB Transition Metal Dichalcogenides

Abstract

Semiconductor technology is currently impaired by the surface dangling bond of materials, which introduces scattering and interface traps. 2D materials, especially transition metal dichalcogenides (TMDs) with different main groups, have settled this issue by utilizing unique atomically smooth surfaces and van der Waals (vdW) structures. Over the past few decades, many processes for exploring new materials, manipulating physical properties, and synthesizing single crystals have been developed. Among these 2D materials, group IVB TMDs are distinguished for their splendid physical properties, including ultrahigh mobility, charge density wave, superconducting transitions, etc. Here, the recent advances in group IVB TMDs are reviewed, which offer easy access to next generation nano-, opto-, thermal-electronic, energy storage and conversion applications. Both the advantages and challenges of these studies are summarized to further clarify existing problems.such as ZrSe 2 is up to 8000 µA µm −1 , which is 10 3 times higher than that of MoS 2 . [11] Group IVB TMDs are also promising thermoelectric materials for their enhanced thermoelectric performance with a high power factor such as TiS 2 . [12][13][14][15][16] These features indicate the great potential of group IVB TMDs for adoption into electronics. In addition, group IVB TMDs show fascinating electrochemical performances as hold materials [17][18][19] or electrodes [20,21] in catalysis [22,23] and batteries [24,25] (Figure 1). A breakthrough may be introduced in nanoelectronic and energy fields for ultrahigh performances and nontoxicity of 2D group IVB TMDs.In this review, we focus on the electronic structures of 1T-phase group IVB TMDs, the abundant properties of group IVB TMDs, and their applications in electronic devices. In particular, we start with the unique crystal structures and calculated electronic structures of 2D group IVB dichalcogenides. Then, the great properties and the current studies in electronic devices are reviewed with an emphasis on recently reported transistor and photodetectors based on group IVB TMD nanosheets. In the third part, the synthesis of group IVBs nanostructures is described. We review the current approaches for the isolation of ultrathin sheets and analyze the advantages and drawbacks of various preparation methods. At last, we present the challenges and future prospects of group IVB TMDs. Crystal and Electronic StructuresThe electronic structures of 2D TMDs strongly depend on their crystal structures and d-electron counts. Another crucial feature is the partially filled d bands of transition metals. Bulk TMDs are composed of ordered stacking monolayers connected by the weak van der Waals (vdW) interaction. This kind of layered material exists multifarious in polymorphs and commonly crystallize into three different structures in 1T, 2H, and 3R phases. For group IVB TMDs, 1T phase is more stable than 2H phase in reversal of group VIB TMDs due to their lower formation energies. [23] Figure 2a,b depicts the two typical structures o...

Two‐Dimensional Layered Metallic VSe2/SWCNTs/rGO Based Ternary Hybrid Materials for High Performance Energy Storage Applications

“…Unlike graphene, single‐layer TMDs are three atom thick, with each layer in TMDs bonded by covalent bonds and these layers are stacked together by weak van der Waals forces . TMDs can be further classified into two structural groups based on the crystal structure, that is, TMDs with trigonal prismatic 2H phase and octahedral 1T phase . The 2H phase is semiconducting in nature, whereas the 1T phase is metallic .…”

Room Temperature Commensurate Charge Density Wave in Epitaxial Strained TiTe2 Multilayer Films

“…The group IVB 2D transition metal dichalcogenides (TMDs) with the chemical formula MX 2 (M = Ti, Hf, and Zr; X = S, Se, and Te) are generally stable adopting a high symmetry trigonal octahedral (1T) structure since they do not possess unpaired d electrons at the metal site that could otherwise be a source of instability. A notable exception is 1T TiSe 2 which, below 205 K makes the transition to a lower symmetry commensurate charge density wave (CDW) ground state associated with a 2 × 2 × 2 periodic lattice distortion (PLD).…”

“…A notable exception is 1T TiSe 2 which, below 205 K makes the transition to a lower symmetry commensurate charge density wave (CDW) ground state associated with a 2 × 2 × 2 periodic lattice distortion (PLD). Despite a large number of studies over the years since the first discovery and a couple of comprehensive reviews the actual mechanism for PLD/CDW formation is still under debate. The most recent experimental and theoretical works focus on the large area growth of the CDW phase the thickness dependence, and the possible unconventional behavior in the ultimate 2D limit of a single layer TiSe 2 .…”

Photodecoloration of Methyl Orange Solution Assisted by ZrS3 Powders

“…The very popular representatives CdS, MoS2 and some others are considered as materials for luminescence [1], photocatalysis [2], piezoelectric materials [3], anodic components for lithium batteries [4], etc. [5].…”