Cooling-mediated One-step Synthesis of Monolayer WSe<sub>2</sub>/WSe<sub>2x</sub>Te<sub>2-2x</sub> Lateral Heterostructures for High-Performance Spectral Photodetectors

ORAL

Abstract

Tellurium (Te) based transition metal dichalcogenides (TMDCs), especially tungsten ditelluride (WTe2), have attracted intensively owing to their unique electrical and optical properties. However, the ternary alloy tungsten selenium telluride (WSe2xTe2-2x) and its lateral hetero-structure with other TMDCs remains largely unexplored due to the considerable challenge in synthesizing these materials, since WTe2 has very weak bonding and tends to decompose at high reaction temperature. Here, we demonstrate a successful one-step synthesis of monolayer WSe2/WSe2xTe2-2x lateral hetero-structures via cooling-mediated chemical vapor deposition. We find that the cooling rate and flow ratio between argon and hydrogen gas are crucial factors for the morphology. The Te incorporation in the alloy is studied by aberration-corrected scanning transmission electron microscopy. The correlation between Te composition and the bandgap of the alloy is simulated by density functional theory. Furthermore, through the study of the optical and electrical properties, we demonstrate the possibility of high-performance spectral photodetectors with spatially graded bandgap.

*
The authors would like to acknowledge ONR support under Grant NAVY N00014-17-1-2973 and NSF support under grant no. ECCS 16-53241 CAR.

–

Presenters

  • Sangmin Kang

    • Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign

Authors

  • Sangmin Kang

    • Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign

  • Chia-Hao Lee

    • Materials Science and Engineering, University of Illinois Urbana-Champaign
    • Department of Material Science and Engineering, University of Illinois at Urbana-Champaign

  • Yifei Li

    • Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign

  • Zijing Zhao

    • Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign

  • Kai Xu

    • Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign

  • Shushan Xia

    • Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign

  • Hojoon Ryu

    • Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign

  • Pinshane Huang

    • Department of Materials Science and Engineering and Materials Research Laboratory, University of Illinois at Urbana-Champaign
    • Materials Science and Engineering, University of Illinois Urbana-Champaign
    • Department of Material Science and Engineering, University of Illinois at Urbana-Champaign

  • Wenjuan Zhu

    • Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign
    • Department of Material Science and Engineering, University of Illinois at Urbana-Champaign