Robotically Manufactured Complex van der Waals Heterostructures for Interlayer-Angle-Controlled Combinatorial Solids

Advancements in the production & processing of 2D materials (2DMs) have been building towards creating complex inter/intra-layer solids, where each specifically-shaped constituent layer amalgamates into a structure that controls X/Y/Z/θ in totality. This is the same design paradigm used in evaporated films for conventional integrated circuits — we use this philosophy to develop our new technique for manufacturing 2DMs combinatorial solids. The technique has three steps: wafer-scale synthesis, polymer-contact-free patterning, and high vacuum dry-transfer automation. We use this to assemble designer van der Waals solids where each spatial region programmatically alters layer number & permuted composition. These solids function as optical spectroscopy assays, where we can study incremental changes in optical response. This technique achieves an unprecedented stacking rate (30 layers/hr) for large-area layers (100 μm)² with few-μm X/Y resolution and <0.2° angle precision. We can also fabricate twisted N-layers; in one instance we observe atomic reconstruction of twisted 4-layer WS₂ at twist angles of ≥4°. Compatibility with pre-fabricated electrodes & multiplexed assembly also imply this technique can parallel manufacture complex electrical circuits without ever breaking vacuum.