Surface‐Functionalization‐Mediated Direct Transfer of Molybdenum Disulfide for Large‐Area Flexible Devices

• Published in: Advanced functional materials 2018-03, Vol.28 (13), p.n/a
• Main Authors: Shinde, Sachin M., Das, Tanmoy, Hoang, Anh Tuan, Sharma, Bhupendra K., Chen, Xiang, Ahn, Jong‐Hyun
• Format: Article
• Language: English
• Subjects: Chemical etching; flexible circuits; Hydrofluoric acid; large‐area transfer; Materials science; metal–organic chemical vapor deposition; Molybdenum disulfide; Organic chemicals; Silicon dioxide; Substrates; Surface energy; Surface treatment; surface‐functionalization
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201706231

The transfer of synthesized large‐area 2D materials to arbitrary substrates is expected to be a vital step for the development of flexible device fabrication processes. The currently used hazardous acid‐based wet chemical etching process for transferring large‐area MoS2 films is deemed to be unsuitable because it significantly degrades the material and damages growth substrates. Surface energy‐assisted water‐based transfer processes do not require corrosive chemicals during the transfer process; however, the concept is not investigated at the wafer scale due to a lack of both optimization and in‐depth understanding. In this study, a wafer‐scale water‐assisted transfer process for metal–organic chemical vapor‐deposited MoS2 films based on the hydrofluoric acid treatment of a SiO2 surface before the growth is demonstrated. Such surface treatment enhances the strongly adhering silanol groups, which allows the direct transfer of large‐area, continuous, and defect‐free MoS2 films; it also facilitates the reuse of growth substrate. The developed transfer method allows direct fabrication of flexible devices without the need for a polymeric supporting layer. It is believed that the proposed method can be an alternative defect‐ and residue‐free transfer method for the development of MoS2‐based next‐generation flexible devices. A minimally disruptive transfer process of wafer‐scale MoS2 film grown by metal–organic chemical vapor deposition (MOCVD) method is developed. The etching‐free transfer process enables the reuse of SiO2 growth substrate, and the fabrication of large‐area, flexible transistors and logic circuits with excellent electrical property and mechanical durability because of the elimination of the unavoidable residue of polymer.