Heterogeneous bonding with 2D nanomaterials: bridging interfaces towards next-generation devices

Two-dimensional (2D) nanomaterials, including atomically thin crystals such as graphene and hexagonal boron nitride, as well as ultrathin metallic films (<100 nm), have emerged as transformative enablers for heterogeneous bonding in next-generation devices. This review comprehensively examines how the unique mechanical and functional properties of 2D materials overcome fundamental limitations of conventional bonding techniques, which are hindered by thermal expansion mismatch, high processing temperatures, and surface roughness sensitivity. We systematically analyze the intrinsic mechanical characteristics of 2D materials—encompassing elastic modulus, fracture strength, as well as thermal and electrical conductivity—that enable conformal, stress-minimized interfaces across dissimilar materials. The review then explores both liquid-state and solid-state bonding mechanisms, highlighting how 2D materials facilitate atomic-scale interface reconstruction at significantly reduced temperatures through mechanisms including van der Waals-mediated contacts, oriented attachment, and transient liquid phase bonding. Applications across multiple domains are discussed, including 3D composites with preserved intrinsic properties, bioelectronic interfaces that seamlessly integrate with biological tissues, microelectronic integration solutions for III-V/Si photonics and back-end-of-line processing, and advanced packaging technologies addressing thermal, mechanical, and electrical challenges simultaneously. The review concludes with a forward-looking perspective on the emerging paradigm of multifunctional bonding interfaces that transcend the single-function role of conventional materials, emphasizing the need for scalable manufacturing, improved interface engineering, and the strategic convergence of different 2D materials to address multiple integration challenges in tandem. This comprehensive analysis establishes 2D nanomaterials as essential components in the evolving landscape of materials integration and device engineering.