2D material printer: a deterministic cross contamination-free transfer method for atomically layered materials

Abstract

Precision and chip contamination-free placement of two-dimensional (2D) materials is expected to accelerate both the study of fundamental properties and novel device functionality. Current transfer methods of 2D materials onto an arbitrary substrate deploy wet chemistry and viscoelastic stamping. However, these methods produce a) significant cross contamination of the substrate due to the lack of spatial selectivity b) may not be compatible with chemically sensitive device structures, and c) are challenged with respect to spatial alignment. Here, we demonstrate a novel method of transferring 2D materials resembling the functionality known from printing; utilizing a combination of a sharp micro-stamper and viscoelastic polymer, we show precise placement of individual 2D materials resulting in vanishing cross contamination to the substrate. Our 2D printermethod results show an aerial cross contamination improvement of two to three orders of magnitude relative to state-of-the-art dry and direct transfer methods. Moreover, we find that the 2D material quality is preserved in this transfer method. Testing this 2D material printer on taped-out integrated Silicon photonic chips, we find that the micro-stamper stamping transfer does not physically harm the underneath Silicon nanophotonic structures such as waveguides or micro-ring resonators receiving the 2D material. Such accurate and substrate-benign transfer method for 2D materials could be industrialized for rapid device prototyping due to its high time-reduction, accuracy, and contamination-free process.

Hybrid silicon photonic devices with two-dimensional materials

“…One of the possible solutions is using Ge-on-Si waveguide to achieve low-loss light transmission in MIR [199,200] because Ge is an ideal material exhibiting high transparency over the entire MIR range (up to ∼14 μm) almost [198]. Definitely, 2D materials are usually flexible and can be transferred to an arbitrary substrate by using the wet-transfer method [65] or the imprint transfer method [66]. Therefore, it is promising to develop photodetection and optical modulation in the MIR range by merging the Ge-on-Si waveguide with 2D materials.…”

“…Furthermore, some 2D materials are very transparent and conductive, and thus can be used as high-efficiency heat conductors or transparent nano-heaters for realizing thermally tunable/switchable silicon photonics devices. In particular, 2D materials can be easily transferred to silicon photonic chips by a wet transfer method [65] or an imprinttransfer process [66]. In this case, there is no lattice match issue.…”

Twistronics: a turning point in 2D quantum materials

“…194 Additionally, micro-stamper technology demonstrated "2D material printing" of mechanically stacked structures with promise for industrial prototyping applications. 195 Despite these impressive results, likely more work needs to be done to make the mechanical transfer method scalable and cost-effective beyond single and niche research applications.…”

Loss and coupling tuning via heterogeneous integration of MoS2 layers in silicon photonics [Invited]

“…transfer of undesired flakes). We recently provided a solution for this challenge developing a 2D material printer enabling cross-contamination-free transfers without impacting the underlying photonic waveguide structures reported in ref [25].…”