The ability to deposit thin and conformal films has become of great importance because of downscaling of devices. However, because of nucleation difficulty, depositing an electrically stable and thin conformal platinum film on an oxide nucleation layer has proven challenging. By using plasma-enhanced atomic layer deposition (PEALD) and TiO 2 as a nucleation layer, we achieved electrically continuous PEALD platinum films down to a thickness of 3.7 nm. Results show that for films as thin as 5.7 nm, the Mayadas–Shatzkes (MS) model for electrical conductivity and the Tellier–Tosser model for temperature coefficient of resistance hold. Although the experimental values start to deviate from the MS model below 5.7 nm because of incomplete Pt coverage, the films still show root mean square electrical stability better than 50 ppm over time, indicating that these films are not only electrically continuous but also sufficiently reliable for use in many practical applications.

The thermomechanical motion imposes the fundamental noise limit in room-temperature resonant sensors and oscillators. Due to the inherently low sensitivity of capacitive transduction in microelectromechanical (MEM) resonators, its effects are often masked by noise in the subsequent amplifier and measurement stages. In this work, we demonstrate a capacitive transduction scheme for measuring kHz-MHz frequency MEM resonators across 1 µm capacitive gaps with 99.8% thermomechanical-noise-limited resolution. We delineate the transimpedance gain and noise of our custom off-chip differential transimpedance amplifier setup. The thermomechanical noise spectrum can provide estimates of the resonant frequency, quality factor, and electromechanical transduction factor comparable to the commonly used driven response, without the downsides of capacitive feedthrough or nonlinearity.

The ability to control the properties of dielectric thin films on demand is of fundamental interest in nanoscale devices. Here, we modulate plasma characteristics at the surface of a substrate to tune both dielectric constant and thermal conductivity of amorphous thin films grown using plasmaenhanced atomic layer deposition. Specifically, we apply a substrate bias ranging from 0 to ∼117 V and demonstrate the systematic tunability of various material parameters of Al 2 O 3 . As a function of the substrate bias, we find a nonmonotonical evolution of intrinsic properties, including density, dielectric constant, and thermal conductivity. A key observation is that the maximum values in dielectric constant and effective thermal conductivity emerge at different substrate biases. The impact of density on both thermal conductivity and dielectric constant is further examined using a differential effective medium theory and the Clausius−Mossotti model, respectively. We find that the peak value in the dielectric constant deviates from the Clausius−Mossotti model, indicating the change of oxygen fraction in our thin films as a function of substrate bias. This finding suggests that the increased local strength of plasma sheath not only enhances material density but also controls the dynamics of microstructural defect formation beyond what is possible with conventional approaches. Based on our experimental observations and modeling, we further build a phenomenological relation between dielectric constant and thermal conductivity. Our results pave invaluable avenues for optimizing dielectric thin films at the atomic scale for a wide range of applications in nanoelectronics and energy devices.

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Mesoporous metals are used in applications requiring high specific surface area and fast mass transport in an electrically conductive network and are primarily produced via dealloying. However, dealloyed metals retain a residual concentration of the sacrificial component, and the final composition of the porous metal is coupled to the same process controls that determine pore size and porosity. The residual component can significantly impact salient physical properties and is a critical contributor to the resistivity of many dealloyed films. To circumvent the impurities introduced by dealloying, we employ block copolymer films as templates to produce three-dimensional bicontinuous films of high-purity electrodeposited nickel and gold. We use this technique to demonstrate decoupling of stoichiometry, pore size, and porosity of mesoporous metals and demonstrate reduced resistivity due to improved material purity. We report electrical resistivity measurements of the films, with nickel and gold exhibiting resistivities of 3.9 × 10–7–6.2 × 10–7 and 2.2 × 10–7–2.4 × 10–7 Ω·m, respectively. The resistivities of the mesoporous metal are substantially lower than many reported values for dealloyed films and close to values predicted by effective medium theory. This work demonstrates a scalable, low-cost, robust platform to prepare mesoporous metals with low resistivity, including myriad electrochemical and thermal systems.