Flexible p-Type WSe₂ Transistors with Alumina Top-Gate Dielectric.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Tungsten diselenide (WSe2) field-effect transistors (FETs) offer tunable polarity for complementary circuits and suitability for flexible electronics via material transfer.
• Achieving high performance in flexible WSe2 FETs remains a challenge, particularly concerning drain currents and charge trapping.

Purpose of the Study:

• To demonstrate flexible p-type WSe2 FETs with high absolute drain currents (|ID|).
• To investigate a fabrication approach utilizing WSe2 grown by metal-organic chemical vapor deposition (MOCVD) and a combined transfer method for flexible electronics.
• To analyze charge trapping effects and their impact on device performance.

Main Methods:

• Fabrication of flexible top-gated WSe2 FETs using a combined WSe2 and metal contact transfer technique.
• Growth of WSe2 via metal-organic chemical vapor deposition (MOCVD) on a sapphire substrate.
• Characterization using pulsed and bias stress measurements to analyze charge trapping.

Main Results:

• Demonstrated flexible p-type WSe2 FETs with absolute drain currents (|ID|) up to 7 μA/μm.
• Achieved high ID on/off ratios (approximately 10^5), comparable or superior to exfoliated single-crystal WSe2 devices.
• Observed preservation of high drain currents during pulsing, indicating minimized charge trapping.

Conclusions:

• The developed fabrication approach is advantageous for achieving high drain currents in flexible 2D transistors.
• The method enables high-performance flexible WSe2 FETs, suitable for emerging electronic applications.
• The study highlights the potential of MOCVD-grown WSe2 and transfer techniques for advanced flexible electronics.