Large-Area Transfer of 2D TMDCs Assisted by a Water-Soluble Layer for Potential Device Applications

Area of Science:

• Materials Science
• Nanotechnology
• Device Physics

Background:

• Industrial implementation of 2D materials requires scalable and clean layer transfer methods.
• Existing methods must preserve the uniformity and cleanliness of as-grown 2D films.
• Wafer-scale fabrication standards necessitate large-area transfer capabilities.

Purpose of the Study:

• To develop a facile, scalable, and clean method for transferring centimeter-scale 2D transition metal dichalcogenides (TMDCs).
• To demonstrate the transfer of various TMDCs (3L MoS2, 1L WS2) onto diverse substrates, including flexible ones.
• To fabricate and characterize a proof-of-concept broadband photodetector using the transferred 2D material.

Main Methods:

• Utilized a water-soluble Na2S/Na2SO4 layer beneath as-grown 2D TMDC films.
• Employed NaOH solution to dissolve the soluble layer, enabling clean detachment of the 2D film.
• Transferred centimeter-scale 3L MoS2 and 1L WS2 onto sapphire, SiO2/Si, mica, and polyimide substrates.

Main Results:

• Successfully transferred 2D TMDCs onto various substrates, preserving uniformity and cleanliness.
• Fabricated a broadband photodetector using transferred 3L MoS2, exhibiting photoresponse from NIR to UV.
• Achieved significant photocurrent enhancement (100x in UV, 10x in visible), high responsivity (8.6 mA/W at 1.5 V), and high detectivity (2.9 x 10^11 Jones).

Conclusions:

• The developed water-soluble layer transfer method is fast, clean, generic, and scalable for 2D atomic layers.
• This technique supports the fabrication of high-performance optoelectronic devices on diverse substrates, including flexible ones.
• Opens pathways for flexible electronics and advanced optoelectronic applications using 2D TMDCs.