engleski

A PDMS-stamp based deterministic transfer of MoS2 for nanopore devices

Single-layer molybdenum disulfide (MoS2) nanopores are ‘blue-energy’ nanopower generators that can act as an ion-selective membranes for osmotic-power generation. To achieve this, the silicon-based MoS2 nanopore devices require extensive microfabrication that comprise of three major steps: substrate fabrication, transfer of MoS2 and nanopore-drilling in MoS2. Transferring monolayer MoS2 (6.5 Å thickness) is a challenging step in device fabrication as it needs to be clean, precise and deterministic for making viable nanopore devices. Usually polymer-based transfer method is used especially poly(methyl methacrylate) (PMMA) which is time- consuming, require post-transfer cleaning steps and introduce detrimental effects in MoS2. Here we demonstrate an alternative improved transfer method based on polydimethylsiloxane (PDMS)-stamps which aid in the transfer of MoS2 from growth substrate (sapphire) to an arbitrary substrate (e.g. silicon nitride). We show that the unlike other PDMS-based methods which either rely on transferring exfoliated samples or capillary-assisted transfer, the current method is more efficient, selective and offer a precision under an optical microscope and avoids using etching solutions (e.g. KOH). The highlights of the method are that it is transfer is achieved within 5-6 minutes, capable of transferring on approx. 10 devices/stamp, and require no-post transfer cleaning. Furthermore, the method can be used to transfer single-to-multi-layer transfer of MoS2 and can be extended to heterostructures.

PDMS, transfer, MoS2, nanopore, deterministic

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