In-Plane 2H-1T' MoTe2 Homojunctions Synthesized by Flux-Controlled Phase Engineering

Youngdong Yoo; Zachary P DeGregorio; Yang Su; Steven J Koester; James E Johns

doi:10.1002/adma.201605461

In-Plane 2H-1T' MoTe₂ Homojunctions Synthesized by Flux-Controlled Phase Engineering

Adv Mater. 2017 Apr;29(16). doi: 10.1002/adma.201605461. Epub 2017 Feb 21.

Authors

Youngdong Yoo¹, Zachary P DeGregorio¹, Yang Su², Steven J Koester², James E Johns¹

Affiliations

¹ Department of Chemistry, University of Minnesota, Minneapolis, MN, 55455, USA.
² Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, 55455, USA.

PMID: 28221704
DOI: 10.1002/adma.201605461

Abstract

The fabrication of in-plane 2H-1T' MoTe₂ homojunctions by the flux-controlled, phase-engineering of few-layer MoTe₂ from Mo nanoislands is reported. The phase of few-layer MoTe₂ is controlled by simply changing Te atomic flux controlled by the temperature of the reaction vessel. Few-layer 2H MoTe₂ is formed with high Te flux, while few-layer 1T' MoTe₂ is obtained with low Te flux. With medium flux, few-layer in-plane 2H-1T' MoTe₂ homojunctions are synthesized. As-synthesized MoTe₂ is characterized by Raman spectroscopy and X-ray photoelectron spectroscopy. Kelvin probe force microscopy and Raman mapping confirm that in-plane 2H-1T' MoTe₂ homojunctions have abrupt interfaces between 2H and 1T' MoTe₂ domains, possessing a potential difference of about 100 mV. It is further shown that this method can be extended to create patterned metal-semiconductor junctions in MoTe₂ in a two-step lithographic synthesis. The flux-controlled phase engineering method could be utilized for the large-scale controlled fabrication of 2D metal-semiconductor junctions for next-generation electronic and optoelectronic devices.

Keywords: 2D materials; MoTe2; TMDCs; junctions; metal-semiconductor.