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The design and fabrication of large-area metamaterials is an ongoing challenge. In the present work, we propose a scalable design route and low-footprint strategy for the production of large-area, frequency-selective Cu–Sn disordered network metamaterials with quasi-perfect absorption. The nanoscale networks combine the robustness of disordered systems with the broad-band optical response known from connected wire-mesh metamaterials. Using experiments and simulations, we show how frequency-selective absorption in the networks can be designed and controlled. We observe a linear dependence of the optical response as a function of Sn content ranging from the near-infrared to the visible region. The absorbing state exhibits strong sensitivity to both changes in the global network topology and the chemistry of the network. We probe the plasmonic response of these nanometric networks by electron energy loss spectroscopy (EELS), where we resolve extremely confined gap surface-plasmon (GSP) modes.

Thermal management is conventionally the design of microelectronics circuitry to maximize heat extraction and minimize local heating. In this work, we investigate a reverse thermal management problem related to understanding and preventing heat dissipation during the propagation of a self-sustained reaction in Ni/Al reactive multilayers, metastable nanostructures that can release heat through a self-sustained propagating exothermic reaction. While it was recently demonstrated that reactive multilayers can serve as on-chip heat sources for on-demand healing of metal films, they still face challenges of device integration due to conductive heat losses to the substrate or adjacent on-chip components, which act as heat sinks and consequently quench the reaction. Here, we study the impact of different heat sink materials, such as gold, copper, and silicon, on the propagation velocity and temperature of the self-sustained heat wave and show that the propagation can be controlled and even stopped by varying the heat sink thickness. Further, we demonstrate that the introduction of a multilayered Al2O3/Zr/Al2O3 thermal barrier enables stable propagation on substrates that would otherwise quench the reaction. The results of this study will facilitate the integration of Ni/Al multilayers as intrinsic heat sources on different substrates for applications in micro/nanodevices.

Self-assembly processes provide the means to achieve scalable and versatile metamaterials by "bottom-up" fabrication. Despite their enormous potential, especially as a platform for energy materials, self-assembled metamaterials are often limited to single phase systems, and complex multi-phase metamaterials have scarcely been explored. We propose a new approach based on sequential self-assembly that enables the formation of a two-phase metamaterial composed of a disordered network metamaterial with embedded nanoparticles. Taking advantage of both the high-spatial and high-energy resolution of electron energy loss spectroscopy, we observe inhomogeneous localization of light in the network, concurrent with dipolar and higher-order localized surface plasmon modes in the nanoparticles. Moreover, we demonstrate that the coupling strength deviates from the interaction of two classical dipoles when entering the strong coupling regime. The observed energy exchange between two phases in this complex metamaterial, realized solely through self-assembly, implies the possibility to exploit these disordered systems for plasmon-enhanced catalysis.

Self‐assembly processes provide the means to achieve scalable and versatile metamaterials by “bottom‐up” fabrication. Despite their enormous potential, especially as a platform for energy materials, self‐assembled metamaterials are often limited to single phase systems, and complex multi‐phase metamaterials have scarcely been explored. A new approach based on sequential self‐assembly (SSA) that enables the formation of a two‐phase metamaterial (TPM) composed of a disordered network metamaterial with embedded nanoparticles (NPs) is proposed. Taking advantage of both the high‐spatial and high‐energy resolution of electron energy loss spectroscopy (EELS), inhomogeneous localization of light in the network is observed, concurrent with dipolar and higher‐order localized surface plasmon modes in the nanoparticles. Moreover, it is demonstrated that the coupling strength deviates from the interaction of two classical dipoles when entering the strong coupling regime. The observed energy exchange between two phases in this complex metamaterial, realized solely through self‐assembly, implies the possibility to exploit these disordered systems for plasmon‐enhanced catalysis.