We describe a simple process for the fabrication of ultrathin, transparent, optically homogeneous, electrically conducting films of pure single-walled carbon nanotubes and the transfer of those films to various substrates. For equivalent sheet resistance, the films exhibit optical transmittance comparable to that of commercial indium tin oxide in the visible spectrum, but far superior transmittance in the technologically relevant 2- to 5-micrometer infrared spectral band. These characteristics indicate broad applicability of the films for electrical coupling in photonic devices. In an example application, the films are used to construct an electric field-activated optical modulator, which constitutes an optical analog to the nanotube-based field effect transistor.

Highly conductive copper nanowires (CuNWs) are essential for efficient data transfer and heat conduction in wide ranging applications like high-performance semiconductor chips and transparent conductors. However, size scaling of CuNWs causes severe reduction in electrical and thermal conductivity due to substantial inelastic surface scattering of electrons. Here we report a novel scalable technique for low-temperature deposition of graphene around CuNWs and observe strong enhancement of electrical and thermal conductivity for graphene-encapsulated CuNWs compared to uncoated CuNWs. Fitting the experimental data with the theoretical model for conductivity of CuNWs reveals significant reduction in surface scattering of electrons at the oxide-free CuNW surfaces, translating into 15% faster data transfer and 27% lower peak temperature compared to the same CuNW without the graphene coating. Our results provide compelling evidence for improved speed and thermal management by adapting the Cu-graphene hybrid technology in future ultrascaled silicon chips and air-stable flexible electronic applications.

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Homogeneous films of pure single wall carbon nanotubes (SWNTs) sufficiently thin to be optically transparent in the visible range of the spectrum were employed as p-Ohmic contacts on GaN−InGaN quantum-well light-emitting diodes. The specific contact resistance of the SWNT films on the p-GaN was 1.1 × 10-2 Ω cm2 after annealing at 700 °C for 60 s under N2, which was a factor of 3 lower than standard Ni/Au contacts on the same p-GaN. The SWNT-contacted LEDs showed bright blue emission centered at 434 nm and demonstrate that the SWNT films provide a new class of electrically conducting, p-type, transparent electrode for use with photonic devices.

Copper interconnects in modern integrated circuits require a barrier layer to prevent Cu diffusion into surrounding dielectrics. However, conventional barrier materials like TaN are highly resistive compared to Cu and will occupy a large fraction of the crosssection of ultra-scaled Cu interconnects due to their thickness scaling limits at 2-3 nm, which will significantly increase the Cu line resistance. It is well understood that ultrathin, effective diffusion barriers are required to continue the interconnect scaling. In this study, a new class of two-dimensional (2D) materials, hexagonal boron nitride (h-BN) and molybdenum disulfide (MoS 2 ), is explored as alternative Cu diffusion barriers. Based on time-dependent dielectric breakdown measurements and scanning transmission electron microscopy imaging coupled with energy dispersive X-ray spectroscopy and electron energy loss spectroscopy characterizations, these 2D materials are shown to be promising barrier solutions for Cu interconnect technology. The predicted lifetime of devices with directly deposited 2D barriers can achieve three orders of magnitude improvement compared to control devices without barriers.