Epitaxial Growth and Determination of Band Alignment of Bi2Te3-WSe2Vertical van der Waals Heterojunctions
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Yang, Chih-Wen
Tang, Hao-Ling
Sattar, Shahid

Chiu, Ming-Hui

Wan, Yi

Chen, Chia Hao

Kong, Jing

Huang, Kuo-Wei

Li, Lain-Jong

Tung, Vincent

KAUST Department
Biological and Environmental Sciences and Engineering (BESE) DivisionChemical Science Program
Homogeneous Catalysis Laboratory (HCL)
KAUST Catalysis Center (KCC)
Material Science and Engineering
Material Science and Engineering Program
Physical Science and Engineering (PSE) Division
KAUST Grant Number
OSR-2018-CARF/CCF3079Date
2020-09-14Online Publication Date
2020-09-14Print Publication Date
2020-10-05Submitted Date
2020-06-13Permanent link to this record
http://hdl.handle.net/10754/665857
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Artificial heterojunctions formed by vertical stacking of dissimilar two-dimensional (2D) transition metal dichalcogenide (TMD) monolayer materials in a chosen sequence hold tantalizing prospects for futuristic atomically thin circuits. The emergence of 2D topological insulators (TI), including Bi2Te3, Bi2Se3, and Sb2Te3, represents a new class of 2D building blocks and can complement the existing artificial heterojunctions as a result of their intriguing surface states protected by the time-reversal symmetry. However, the determination of band alignments of such 2D TI/TMD vertical heterojunctions, the key parameter for designing HJ-based electronic/photonic devices, which lies in the development of epitaxy growth, remains in its infancy. Here, we demonstrate the epitaxy growth of 2D TI/TMD vertical heterojunctions comprised of Bi2Te3/WSe2 with atomically clean interfaces that are spectroscopically accessible, and theoretically tractable. Cross-sectional scanning transmission electron microscopy (STEM) images and the presence of interlayer-coupled characteristics from Raman spectroscopy collectively confirm the neat stacking of Bi2Te3/WSe2 with the absence of unwanted containments. Microbeam X-ray photoelectron spectroscopy (μXPS) measurement coupled with the density functional theory (DFT) calculations and electrical characteristics of field effect transistors quantitatively reveals the type-II alignment of vertically stacked of quintuple layers (QL) Bi2Te3/WSe2. Meanwhile, the type-III band emerges when transitioning to multi-quintuple layer (MQL) Bi2Te3/WSe2. The finding here provides a well-defined example of the epitaxy growth paradigm, the interlayer coupling-electronic properties relationship, for these emerging 2D TI/TMDs vertical heterojunctions.Citation
Yang, C.-W., Tang, H.-L., Sattar, S., Chiu, M.-H., Wan, Y., Chen, C.-H., … Tung, V. (2020). Epitaxial Growth and Determination of Band Alignment of Bi2Te3–WSe2 Vertical van der Waals Heterojunctions. ACS Materials Letters, 2(10), 1351–1359. doi:10.1021/acsmaterialslett.0c00254Sponsors
V.T., and M.-H.C. are indebted to the support from the King Abdullah University of Science and Technology (KAUST), KAUST Catalysis and Solar Centres, and Office of Sponsored Research (OSR) under Award No: OSR-2018-CARF/CCF3079. S.S. thanks High Performance Computing Center North (HPC2N) National Supercomputer Center in Linkping (NSC) for allocation of time and resources, through the Swedish National Infrastructure for Computing (SNIC). H.-L.T. acknowledges the partial support from the Ministry of Science and Technology of Taiwan (MOST-108-2917-I-564-036). We thank Prof. D. A. Muller and Dr. Z. Chen for the helpful discussion on STEM and Prof. Q. Tong for the useful discussion on DFT simulations.Publisher
American Chemical Society (ACS)Journal
ACS Materials LettersAdditional Links
https://pubs.acs.org/doi/10.1021/acsmaterialslett.0c00254ae974a485f413a2113503eed53cd6c53
10.1021/acsmaterialslett.0c00254