• search hit 5 of 6
Back to Result List

Thermodynamic Evaluation and Chemical Vapor Transport of Few-Layer WTe2

  • Tungsten telluride WTe2 is the sole candidate of a group of two-dimensional layered transition metal dichalcogenides (TMDCs) MX2 with a thermodynamically stable 1T′-structure at room temperature. The binary system W/Te was audited with respect to a rational approach of planning and realization of a bottom-up synthesis of WTe2 nanostructures. Thus, the parameters of the synthesis via chemical vapor transports (CVT) were derived by thermodynamic simulations of the reaction pathway according to the Calphad method. Reflecting on the peritectic melting behavior at 1020 °C, the values of ΔfHm° (298 K) = −26.5 kJ·mol−1 and Sm° (298 K) = 132 J·mol−1 ·K−1 have been obtained. According to modeling, crystal growth by short time vapor transport is reasonable under the addition of bromine or TeBr4 in the temperature range between 650 and 750 °C. Experimental implementation of crystal growth of WTe2 nanosheets succeeded in a temperature gradient from 725 to 675 °C on yttria-stabilized zirconia (YSZ) (111) substrates, observing the deposition ofTungsten telluride WTe2 is the sole candidate of a group of two-dimensional layered transition metal dichalcogenides (TMDCs) MX2 with a thermodynamically stable 1T′-structure at room temperature. The binary system W/Te was audited with respect to a rational approach of planning and realization of a bottom-up synthesis of WTe2 nanostructures. Thus, the parameters of the synthesis via chemical vapor transports (CVT) were derived by thermodynamic simulations of the reaction pathway according to the Calphad method. Reflecting on the peritectic melting behavior at 1020 °C, the values of ΔfHm° (298 K) = −26.5 kJ·mol−1 and Sm° (298 K) = 132 J·mol−1 ·K−1 have been obtained. According to modeling, crystal growth by short time vapor transport is reasonable under the addition of bromine or TeBr4 in the temperature range between 650 and 750 °C. Experimental implementation of crystal growth of WTe2 nanosheets succeeded in a temperature gradient from 725 to 675 °C on yttria-stabilized zirconia (YSZ) (111) substrates, observing the deposition of single crystal sheets of high crystallinity with thicknesses of 15−20 nm (∼20−30 layers). The high crystallinity, pristine morphology, and overall quality of the deposited nanosheets is shown by means of atomic resolution transmission electron microscopy, selected area electron diffraction (SAED), and atomic force microscopy as well as profound double-polarized Raman spectroscopy.show moreshow less

Export metadata

Additional Services

Search Google Scholar
Metadaten
Author: Felix HansenORCiD, Martin Wels, Samuel FroeschkeORCiD, Alexey PopovORCiD, Daniel WolfORCiD, Bernd BüchnerORCiD, Peer SchmidtORCiD, Silke HampelORCiD
URL:https://pubs.acs.org/doi/abs/10.1021/acs.cgd.0c01004
DOI:https://doi.org/10.1021/acs.cgd.0c01004
ISSN:1528-7505
Title of the source (English):Crystal Growth and Design
Document Type:Scientific journal article peer-reviewed
Language:English
Year of publication:2020
Tag:2D layered compounds; Chalcogenides; Chemical vapor transport; Crystal growth; Phase diagram; Thermodynamic modeling
Volume/Year:20
Issue number:11
First Page:7341
Last Page:7349
Faculty/Chair:Fakultät 2 Umwelt und Naturwissenschaften / FG Anorganische Chemie
Einverstanden ✔
Diese Webseite verwendet technisch erforderliche Session-Cookies. Durch die weitere Nutzung der Webseite stimmen Sie diesem zu. Unsere Datenschutzerklärung finden Sie hier.