Highly Efficient Postprocessing Cleaning of van der Waals Devices

Abstract

Interfacial contaminants remain a major technical challenge for van der Waals (vdW) junctions, severely degrading device performance. Given the inherent difficulty of fabricating contaminant-free vdW interfaces, developing effective postfabrication cleaning technologies is crucial for restoring interfacial quality. Existing technologies include annealing, which results in incomplete removal, and AFM-tip squeezing, which is time-consuming and costly. Here, we invent a complete, rapid, and cost-effective electric-field-assisted cleaning method that simultaneously delivers high spatial and temporal efficiency. For a microscale graphite interface, this method removes over 95% of the contaminant coverage within just 20 ms, restoring the interfacial conductivity to its clean-state level without introducing defects. Compared with previous methods, our method achieves a comparable or higher level of contaminant removal while reducing the required time by at least 4 orders of magnitude. We further demonstrate its practical applicability using a microscale superlubric Schottky generator, which transitions from an insulative to a generating state after cleaning. Importantly, the interfacial cleanliness level achieved by our method satisfies U.S. cleanliness standards for aerospace, semiconductor manufacturing, and medical devices, suggesting its broad applicability across multiple industries.