A flow-through microfluidic channel is equipped with miniaturized electrodes to investigate calcite dissolution. Microscale visual detection aids in the interpretation of spectral induced polarization (SIP) monitoring.

Previous studies have shown that undoped and doped SnO₂ thin films have better optical and electrical properties. This study aims to investigate the thermoelectric properties of two distinct semiconducting oxide thin films, namely SnO₂ and F-doped SnO₂ (FTO), by the nebulizer spray pyrolysis technique. An X-ray diffraction study reveals that the synthesized films exhibit a tetragonal structure with the (200) preferred orientation. The film structural quality increases from SnO₂ to FTO due to the substitution of F⁻ ions into the host lattice. The film thickness increases from 530 nm for SnO₂ to 650 nm for FTO films. Room-temperature electrical resistivity decreases from (8.96 ± 0.02) × 10⁻² Ω·cm to (4.64 ± 0.01) × 10⁻³ Ω·cm for the SnO₂ and FTO thin films, respectively. This is due to the increase in the carrier density of the films, (2.92 ± 0.02) × 10¹⁹ cm⁻³ (SnO₂) and (1.63 ± 0.03) × 10²⁰ cm⁻³ (FTO), caused by anionic substitution. It is confirmed that varying the temperature (K) enhances the electron transport properties. The obtained Seebeck coefficient (S) increases as the temperature is increased, up to 360 K. The synthesized films exhibit the S value of −234 ± 3 μV/K (SnO₂) and −204 ± 3 μV/K (FTO) at 360 K. The estimated power factor (PF) drastically increases from ~70 (μW/m·K²) to ~900 (μW/m·K²) for the SnO₂ and FTO film, respectively.

This paper explores the microfabrication process of plasma reactors, from the production of micro-reactors to the addition of through silicon vias (TSV) using proprietary etching techniques and on site cleanroom facilities. The investigation focuses on both newly fabricated closed and open-cavity micro-hollow cathode discharge (MHCD) reactors, with particular emphasis on electrical and optical diagnostics to characterize their plasma properties. All experiments, including those on closed-cavity reactors, were specifically conducted for this study under identical conditions to ensure a rigorous comparison between reactor types. When electrical diagnostics were carried out in helium at various pressures, interesting phenomena such as the evolution of voltage breakdown were observed. These diagnostics also provided new insights into the impact of surface electrode and overall geometry properties and pressure on reactor performance. Additional investigation into instability mechanisms revealed self-pulsing oscillations, with different reactor types having different oscillation amplitudes for similar operating conditions. Optical emission spectroscopy (OES) emerged as a strong tool for spatial plasma analysis, revealing consistent gas temperature distributions across reactor diameters. The Inglis-Teller series provided an estimate of the upper limit of electron density, while the Stark broadening analysis of H α offered valuable insights into electron density variations, particularly in the self-pulsing regime.

Nanographene–mesoporous silicon (G-PSi) composites have recently emerged as a promising class of nanomaterials with tuneable physical properties. In this study, we investigated the impact of nanographene coating on the Seebeck coefficient of mesoporous silicon (PSi) obtained by varying two parameters: porosity and thickness. To achieve this, an electrochemical etching process on p + doped Si is presented for the control of the parameters (thicknesses varying from 20 to 160 µm, and a porosity close to 50%), and for nanographene incorporation through chemical vapor deposition. Raman and XPS spectroscopies confirmed the presence of nanographene on PSi. Using a homemade ZT meter, the Seebeck coefficient of the p + doped Si matrix was evaluated at close to 100 ± 15 µV/K and confirmed by UPS spectroscopy analysis. Our findings suggest that the Seebeck coefficient of the porous Si can be measured independently from that of the substrate by fitting measurements on samples with a different thickness of the porous layer. The value of the Seebeck coefficient for the porous Si is of the order of 750 ± 40 µV/K. Furthermore, the incorporation of nanographene induced a drastic decrease to approximately 120 ± 15 µV/K, a value similar to that of its silicon substrate.