Fabrication of an Aluminum-Based Thermoelectric Module Substrate via Anodization and Nickel Plating.

In this study, a thermoelectric module substrate was fabricated by subjecting an aluminum plate to a surface treatment process. To achieve this, the aluminum-based substrate was carried out to electrolytic etching, anodization, and Ni plating. The anodization of aluminum created an oxide film, which served as an insulation layer, while the Ni plating formed a conductive circuit layer. The substrate fabricated in this study exhibited excellent insulation performance, demonstrating its potential for future use in thermoelectric module substrates. Its adhesion properties were verified using a cross-cut adhesion test; microstructures of the surface and cross-section revealed the successful formation of the oxide film and Ni circuit layers on the aluminum base. From the results of these, it is clearly confirmed that the anodized aluminum substrate developed in this study provides suitable insulating performances and bonding nature with Ni electrode.

High-Field Electron Transport and High Saturation Velocity in Multilayer Indium Selenide Transistors.

Creating a high-frequency electron system demands a high saturation velocity (υsat). Herein, we report the high-field transport properties of multilayer van der Waals (vdW) indium selenide (InSe). The InSe is on a hexagonal boron nitride substrate and encapsulated by a thin, noncontinuous In layer, resulting in an impressive electron mobility reaching 2600 cm2/(V s) at room temperature. The high-mobility InSe achieves υsat exceeding 2 × 107 cm/s, which is superior to those of other gapped vdW semiconductors, and exhibits a 50-60% improvement in υsat when cooled to 80 K. The temperature dependence of υsat suggests an optical phonon energy (ℏωop) for InSe in the range of 23-27 meV, previously reported values for InSe. It is also notable that the measured υsat values exceed what is expected according to the optical phonon emission model due to weak electron-phonon scattering. The superior υsat of our InSe, despite its relatively small ℏωop, reveals its potential for high-frequency electronics, including applications to control cryogenic quantum computers in close proximity.