Hydrophilic Substrates: A Key toward Wrinkle-Free Wet Transfer of Two-Dimensional Materials

Area of Science:

• Materials Science
• Nanotechnology
• Solid State Physics

Background:

• Two-dimensional transition metal dichalcogenides (TMDs) are promising semiconductors for electronics and optoelectronics.
• Current transfer methods for TMDs often result in imperfect interfaces and poor device performance.

Purpose of the Study:

• To develop a method for wrinkle-free transfer of monolayer WS2 films.
• To enhance the performance of WS2-based field-effect transistors (FETs) and phototransistors.

Main Methods:

• Utilizing a hydrophilic atomic layer-deposited (ALD)-Al2O3 layer as a target substrate for wet transfer.
• Fabricating FETs and phototransistors using monolayer WS2 on ALD-Al2O3/SiO2 and SiO2 gate dielectrics.
• Characterizing film uniformity using photoluminescence and device performance metrics.

Main Results:

• Achieved wrinkle-free transfer of monolayer WS2 films on ALD-Al2O3-mediated substrates.
• Demonstrated an 80% reduction in hysteresis in WS2 FETs with ALD-Al2O3/SiO2 gate dielectric.
• Obtained an electron mobility of 15.81 cm2·V−1·s−1 using Al2O3 as a high-k gate dielectric.
• Reported a phototransistor responsivity of 1354 A·W−1.

Conclusions:

• Hydrophilic substrates facilitate wrinkle-free transfer of 2D materials.
• The ALD-Al2O3 interlayer enhances the performance of WS2-based electronic and optoelectronic devices.
• This method provides a viable route for high-quality 2D material integration and improved device functionality.