Spatially composition-graded monolayer tungsten selenium telluride
Abstract
Heterogeneous materials with spatially modulated bandgaps have many unique applications, such as super-broadband nanolasers, color engineered displays, hyperspectral detectors, and full spectrum solar cells. In this work, spatially composition-graded WSe2 − 2xTe2x flakes are synthesized through an in situ chemical vapor deposition method. Furthermore, a monolayer flake topography is confirmed by atomic force microscopy. Photoluminescence and Raman line-scanning characterization indicate the bandgap changes continuously from center (1.46 eV) to edge (∼1.61 eV) within a monolayer flake. Electronic devices based on this spatially composition-graded material exhibit tunable transfer curves. First principal calculation reveals that the electron affinity increases, while the bandgap decreases based on tellurium composition. This is consistent with experimentally observed non-monotonic dependence of the hole current on tellurium composition. This work provides the experimental groundwork for synthesis of the composition-graded transition metal dichalcogenide materials and offers a route toward tailoring their electrical properties by bandgap engineering in the future.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jun 06, 2022
- Source ID
- 10.1063/5.0094658
Entities
People
- Changqiang Chen
- Hussain Alsalman
- Junzhe Kang
- Kai Xu
- Tony Low
- Wenjuan Zhu
- Zheng Hao
- Zhiyu Wang
- Zijing Zhao
Organizations
- King Abdulaziz City for Science and Technology
- National Science Foundation
- Office of Naval Research
- Semiconductor Research Corporation
- University of Illinois Urbana–Champaign
- University of Minnesota