Related Experiment Video
Updated: Mar 18, 2026
08:50
Preparation of Large-area Vertical 2D Crystal Hetero-structures Through the Sulfurization of Transition Metal Films for Device Fabrication
Published on: November 28, 2017
9.7K
Growth of Low-Defect WSe2 Film via High-Purity van der Waals Crystal Precursor
Hang Liu1, Ni Yang2, Jiacheng Min2,3
1Division of Physical Science and Engineering (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia.
ACS Nano
|March 16, 2026
Summary
We identified key defects impacting p-type WSe2 quality and developed a physical vapor deposition (PVD) method to grow high-purity films. This method achieves record hole mobility for 2D WSe2, advancing nanoelectronics.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDs) are crucial for nanoelectronics due to their unique properties.
- High-mobility p-type 2D TMDs, particularly WSe2, remain challenging to synthesize, hindering device applications.
- Defects significantly influence the electronic properties of 2D materials.
Purpose of the Study:
- To investigate the influence of substitutional impurity defects on the quality of 2D p-type WSe2.
- To develop a method for synthesizing high-purity monolayer 2D WSe2 with controlled defects.
- To achieve high hole mobility in synthesized WSe2 for advanced nanoelectronic applications.
Main Methods:
- Density functional theory (DFT) calculations to predict the impact of various substitutional defects.
- Physical Vapor Deposition (PVD) using van der Waals (vdW) crystals as precursors to grow monolayer 2D WSe2 (VPVD-WSe2).
- Spectroscopy and scanning tunneling microscopy (STM) to characterize defect density and film quality.
- Fabrication and electrical characterization of field-effect transistors (FETs) based on VPVD-WSe2.
Main Results:
- DFT identified Fe, Co, Ni, and Si as detrimental substitutional W defects, while O, S, and Mo had negligible impact.
- A facile vdW crystal PVD method yielded centimeter-scale, continuous, high-purity monolayer 2D WSe2 (VPVD-WSe2) with ultralow substitutional impurity defects.
- VPVD-WSe2 exhibited significantly reduced defect density compared to chemical vapor deposition (CVD) and other PVD methods.
- VPVD-WSe2 based FETs achieved a record-high field-effect hole mobility of 112 cm^2 V^-1 s^-1 at room temperature.
Conclusions:
- Substitutional impurity defects critically affect 2D p-type WSe2 quality, with specific elements posing greater challenges.
- The developed vdW crystal PVD method is effective for synthesizing high-quality, large-area monolayer 2D WSe2.
- The achieved high hole mobility demonstrates the potential of VPVD-WSe2 for next-generation nanoelectronic devices.
