Effects of growth substrate on the nucleation of monolayer MoTe<sub>2</sub>

Hynek, David; Singhania, Raivat M.; Hart, James L.; Davis, B. E. C.; Wang, Mengjing; Strandwitz, Nicholas C.; Judy, J.

doi:10.1039/d1ce00275a

Cited by 4 publications

(2 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We find that monolayer WTe 2 flakes are observed on sapphire but not on SiO 2 for the same WO x film thickness, which is similar to our previous results for the growth of MoTe 2 thin films. [ 15,25 ] However, unlike MoTe 2 that formed continuous films with thickness control, we observe the formation of WTe 2 flakes on both sapphire and SiO 2 instead of continuous films. We attribute this to the lower reactivity of W with Te and weaker substrate interactions between W and sapphire than between Mo and sapphire, resulting in a greater likelihood of isolated flake formation.…”

Section: Introductionmentioning

confidence: 58%

“…[ 15 ] We also showed that the choice of growth substrate impacts the phase stability and large‐scale uniformity of MoTe 2 monolayer films. [ 25 ] The large grains in 2H MoTe 2 films were obtained by first synthesizing 1T′ MoTe 2 films from the starting oxide film, and then converting the 1T′ MoTe 2 to 2H MoTe 2 . In contrast to MoTe 2 , WTe 2 is stable at room temperature in the T d phase, which is structurally identical to the 1T′ phase in‐plane but with different layer stacking.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Substrate Effects on Growth Dynamics of WTe₂ Thin films

Hynek

Onder

Hart

et al. 2023

Adv Materials Inter

Self Cite

View full text Add to dashboard Cite

Synthesis of transition metal dichalcogenides (TMDCs) has been achieved through the direct conversion of metal and metal‐oxide films, demonstrating the ability to grow large area thin films with uniform thickness on a variety of substrates and direct control over the growth orientation (horizontal vs vertical) of the TMDC layers. However, the synthesized TMDC films often exhibit small grains and are more defective than their bulk counterparts. This is especially true for 2D telluride films due to the low reactivity between tellurium and transition metals such as W and Mo. In this work, the substrate interactions is examined for WTe2 converted from amorphous WOx thin films grown by atomic layer deposition, on c‐plane sapphire and SiO2 through tellurization at high temperatures. Similar to TMDC telluride MoTe2, the formation of monolayer WTe2 on sapphire is observed, but not on SiO2. However, due to decreased diffusion of W on sapphire compared to Mo, the formation of WTe2 flakes instead of continuous films is observed, providing insight into the role of the specific transition metal during the direct synthesis of TMDC telluride films.

show abstract

Section: Introductionmentioning

confidence: 58%

Section: Introductionmentioning

confidence: 99%

Substrate Effects on Growth Dynamics of WTe₂ Thin films

Hynek

Onder

Hart

et al. 2023

Adv Materials Inter

Self Cite

View full text Add to dashboard Cite

show abstract

Two‐Step Conversion of Metal and Metal Oxide Precursor Films to 2D Transition Metal Dichalcogenides and Heterostructures

Altvater,

Muratore,

Snure

et al. 2024

Small

View full text Add to dashboard Cite

The widely studied class of two‐dimensional (2D) materials known as transition metal dichalcogenides (TMDs) are now well‐poised to be employed in real‐world applications ranging from electronic logic and memory devices to gas and biological sensors. Several scalable thin film synthesis techniques have demonstrated nanoscale control of TMD material thickness, morphology, structure, and chemistry and correlated these properties with high‐performing, application‐specific device metrics. In this review, the particularly versatile two‐step conversion (2SC) method of TMD film synthesis is highlighted. The 2SC technique relies on deposition of a solid metal or metal oxide precursor material, followed by a reaction with a chalcogen vapor at an elevated temperature, converting the precursor film to a crystalline TMD. Herein, the variables at each step of the 2SC process including the impact of the precursor film material and deposition technique, the influence of gas composition and temperature during conversion, as well as other factors controlling high‐quality 2D TMD synthesis are considered. The specific advantages of the 2SC approach including deposition on diverse substrates, low‐temperature processing, orientation control, and heterostructure synthesis, among others, are featured. Finally, emergent opportunities that take advantage of the 2SC approach are discussed to include next‐generation electronics, sensing, and optoelectronic devices, as well as catalysis for energy‐related applications.

show abstract

Two step synthesis of ultrathin transition metal tellurides

Snure

Motala

Prusnick³

et al. 2022

Journal of Vacuum Science &Amp; Technology A

View full text Add to dashboard Cite

Transition metal tellurides (TMTs) are an exciting group of two-dimensional materials with a wide variety of polytypes and properties. Here, we demonstrate a simple and versatile two-step method for producing MoTe2, WTe2, and PtTe2 films via tellurization of thin metals at temperatures between 400 and 700 °C. Across this temperature range, monoclinic 1T′ phase of MoTe2, orthorhombic Td phase of WTe2, and hexagonal 2H phase of PtTe2 were formed. Based on x-ray diffraction and Raman analysis, temperatures greater than 600 °C were found to produce the best quality MoTe2 and WTe2. In contrast, lower temperatures (400 °C) were preferred for PtTe2, which becomes discontinuous and eventually decomposes above 650 °C. The presence of H2 in the tellurization process was critical to facilitate the formation of H2Te, which is known to be more reactive than Te vapor. In the absence of H2, neither MoTe2 nor WTe2 formed, and although PtTe2 was formed under pure N2, the crystal quality was significantly reduced. Temperature-dependent resistivity (ρ) measurements were performed on the best quality TMT films revealing all films to be highly conductive. MoTe2 showed metallic behavior up to 205 K where it underwent a phase transition from the semimetallic Td to semiconducting 1T′ phase. WTe2 exhibited a consistent semiconducting behavior with a small positive increase in ρ with decreasing temperature, and PtTe2 showed a metallic dependence from 10 K up to room temperature. Spectroscopic ellipsometry for TMT films provides complex optical constants n and k from ultraviolet to infrared.

show abstract

Effects of growth substrate on the nucleation of monolayer MoTe₂

Abstract: The discovery and characterization of two-dimensional (2D) materials beyond graphene has increased dramatically over the past decade with increasingly fine control over the growth dynamics of these materials. MoTe2 represents...

Cited by 4 publications

References 30 publications

Substrate Effects on Growth Dynamics of WTe₂ Thin films

Substrate Effects on Growth Dynamics of WTe₂ Thin films

Two‐Step Conversion of Metal and Metal Oxide Precursor Films to 2D Transition Metal Dichalcogenides and Heterostructures

Two step synthesis of ultrathin transition metal tellurides

Contact Info

Product

Resources

About

Effects of growth substrate on the nucleation of monolayer MoTe2

Abstract: The discovery and characterization of two-dimensional (2D) materials beyond graphene has increased dramatically over the past decade with increasingly fine control over the growth dynamics of these materials. MoTe2 represents...

Cited by 4 publications

References 30 publications

Substrate Effects on Growth Dynamics of WTe2 Thin films

Substrate Effects on Growth Dynamics of WTe2 Thin films

Two‐Step Conversion of Metal and Metal Oxide Precursor Films to 2D Transition Metal Dichalcogenides and Heterostructures

Two step synthesis of ultrathin transition metal tellurides

Contact Info

Product

Resources

About

Effects of growth substrate on the nucleation of monolayer MoTe₂

Substrate Effects on Growth Dynamics of WTe₂ Thin films

Substrate Effects on Growth Dynamics of WTe₂ Thin films