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Atomic layer deposited Al2O3passivation layer for few-layer WS2field effect transistors.
Young Gyu You1, Dong Ho Shin1, Jong Hwa Ryu1
1Department of Physics, Konkuk University, Seoul 05029, Republic of Korea.
Nanotechnology
|September 3, 2021
Summary
Adding an aluminum oxide (Al2O3) passivation layer improves the performance and stability of few-layer tungsten disulfide field-effect transistors (WS2 FETs). This layer enhances carrier mobility and reduces Schottky barriers, leading to more reliable devices.
Area of Science:
- Materials Science
- Nanoscience
- Solid State Physics
Background:
- Few-layer tungsten disulfide field-effect transistors (WS2 FETs) performance is often limited by charged impurities and Schottky barriers.
- These limitations lead to decreased carrier mobility and hinder device efficiency.
Purpose of the Study:
- To investigate the impact of an aluminum oxide (Al2O3) passivation layer on WS2 FET performance.
- To understand the mechanisms behind performance enhancement and stability improvement.
Main Methods:
- Fabrication of few-layer WS2 FETs.
- Atomic layer deposition (ALD) of an Al2O3 overlayer.
- Electrical characterization of WS2 FETs before and after Al2O3 deposition.
- Analysis of carrier mobility, Schottky barrier height, and device stability.
Main Results:
- Al2O3 passivation suppressed charged impurity effects via high-κ dielectric screening.
- The Al2O3 layer reduced the effective Schottky barrier height, attributed to n-doping from positive fixed charges at the Al2O3/WS2 interface.
- WS2 FETs with Al2O3 passivation exhibited enhanced and stable electrical performance over 57 days, resisting oxidation.
Conclusions:
- ALD of Al2O3 is an effective method to enhance the performance of few-layer WS2 FETs.
- The Al2O3 passivation layer significantly improves device stability and ambient resistance.
- This approach offers a facile route to high-performance and stable WS2-based electronic devices.
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