Transfer-free, scalable vertical heterostructure FET on MoS2/WS2continuous films
Merve Acar1, Mehmet Ertuğrul1,2, Emre Gür2,3
1Department of Electrical and Electronics Engineering, Faculty of Engineering, Atatürk University, 25240, Erzurum, Turkey.
Nanotechnology
|August 15, 2022
Summary
This study presents a scalable method for creating continuous MoS2/WS2 vertical heterojunction films for advanced electronics. These films demonstrate significantly enhanced electron mobility and on/off ratios, paving the way for high-performance field-effect transistors (FETs).
Area of Science:
- Materials Science: Focuses on the synthesis and characterization of novel 2D material heterostructures.
Background:
- Molybdenum disulfide (MoS2) and tungsten disulfide (WS2) possess unique layered structures and electronic properties.
- Vertical heterojunctions of MoS2/WS2 are of high demand due to their potential in electronic devices.
Purpose of the Study:
- To develop a continuous, scalable, and transfer-free method for fabricating MoS2/WS2 vertical heterojunction films.
- To investigate the electrical properties and performance of field-effect transistors (FETs) based on these heterojunctions.
Main Methods:
- Fabrication of MoS2/WS2 vertical heterojunction films using sputtering deposition on amorphous SiO2/Si substrates.
- Characterization using RAMAN spectroscopy to confirm heterostructure formation and X-ray Photoelectron Spectroscopy (XPS) to verify layer integrity.
- Fabrication and electrical testing of numerous FETs on the synthesized heterojunction films.
Main Results:
- Successful creation of continuous, scalable MoS2/WS2 vertical heterojunction films without a transfer step.
- RAMAN and XPS confirmed the formation of distinct MoS2 and WS2 layers, not an alloy.
- MoS2/WS2 heterostructure FETs exhibited tunable polarity (p-type to ambipolar to n-type) with varying drain voltages.
- Significantly enhanced electron mobility (7.2 cm2V.s-1) and on/off ratios (104-105) compared to individual MoS2 or WS2 devices.
Conclusions:
- The developed sputtering method provides a viable route for commercializing MoS2/WS2 heterojunction films.
- The MoS2/WS2 heterostructure FETs show superior electrical performance, making them promising for future nanoelectronic logic devices.
- This work demonstrates progress in carrier-type controlled, high-performance heterojunction-based FETs.
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