Monolayer MoS2 Transferred on Arbitrary Substrates for Potential Use in Flexible Electronics

Molybdenum disulfide (MoS2), having unique optical and electrical properties, is a promising material for both nanoscale and flexible electronics. Direct growth of MoS2 over various substrates is possible by using several synthesis routes. But there is a pressing need for clean and damage-free transfer of MoS2 from the growth substrate onto other substrates for structural characterizations and novel device fabrication. In this work, we report about an efficient and clean route that can be applied for the transfer of MoS2 over any other substrate. The proposed transfer route is based on the dissolution of the water-soluble layer (Na2S/Na2SO4) formed underneath MoS2 flakes simultaneously during the growth process. The results from optical, morphological, and transmission electron microscopy characterizations show that the transfer process is clean and damage-free. Also, there is no significant change in morphology and quality of the transferred MoS2 layers. We have shown that the crystalline quality of MoS2 transferred by this approach is much better than the conventional transfer method. Furthermore, the proposed process allows the reuse of the growth substrate, which makes it an inexpensive process. This process may also be used for the transfer of other 2D materials (e.g., TMDCs) on any other substrate of choice. Also, this transfer approach paves the way for heterointegration of MoS2 with other materials and provides the opportunities to fabricate the flexible electronic and optoelectronic devices based on MoS2.