ICMCTF 2026 Session TS2-1-WeA: Coatings and Surfaces for Renewable Energy Technology I

Scandium nitride (ScN) is a cubic NaCl-structured, degenerated narrow-bandgap n-type semiconductor with an indirect bandgap of ∼0.9 eV and a direct band gap estimated at around 2.6 eV. It has remarkable semiconducting phonon-polariton application, electrical, thermoelectric and piezoelectric application. The physical properties of ScN nitride are sensitive to defects such as crystal defect, morphology, intentional or unintentional doping. In this work, the impact of strain on the electrical transport properties and optical properties has been investigated. For the purpose of reducing the deposition temperature of ScN, High power impulse magnetron sputtering (HIPIMS) technique was used to produce a series of film on c-sapphire in a 250-850 °C temperature range. The composition and overall crystal structure of the film remained relatively the same in the sample series while its optical and electrical properties were deteriorated upon temperature decrease. Using in depth XRD, optical and electrical characterization, the effect of strain and dislocation on the semiconductor properties of ScN was evaluated. A reduction of deposition temperature from 850 °C to 450 °C yield a slow degradation of the electrical, and optical properties to a drastic change for a film deposited below 450 °C. Below 450 °C, the films present a high dislocation density (10¹¹ m^-2) along with a rhombohedral distortion of ScN cell (α: 90° → 88.6°) being the main cause of electrical transport deterioration (σ/10000; n/100, μ/100). The presence of dislocation / crystal defect in the film creates defect states near the valence and conduction bands which impact the electron density, hence their correlated electrical transport and thermoelectric properties. To the best the ScN shows promising thermoelectric properties and having an orange appearance when grown at high temperatures while behaving like a poor semiconductor with a black appearance when grown at low temperature.

As we move toward a greener economy, sustainability must be at the core of any technological advancement. In a future filled with smart devices and driven by the Internet of Things (IoT), the design of integrated electronic circuits requires new approaches that target environmental friendliness, and renewable energy sources for power. Our efforts in this direction focus on harvesting energy from sustainable sources following standard Integrated circuits (IC) techniques. In the talk, innovative approaches for on-chip thermoelectric devices (TED) will be presented, exploiting silicon nanostructures as core components, and based on classic IC fabrication technologies[1,2]. The reason for using silicon nanostructures stems from their distinctive properties in terms of electrical conductivity and Seebeck coefficient, which can be tailored with technological solutions, and low thermal conductivity. Two strategies will be discussed. The first focuses on enhancing the Seebeck coefficient via the energy filtering effect, achieved by introducing multiple energy barriers, each tens of nanometers wide, through selective doping of silicon nanomembranes. The second involves the development of a prototype on-chip TED that integrates numerous silicon nanobeams into a compact device measuring only a few square millimeters. These devices can generate several milliwatts of power from hot surfaces, enabling low-power electronic systems, such as sensor nodes, to operate in a battery-less mode.

[1] E.Dimaggio, A.Masci, A. De Seta, M.Salleras, L.Fonseca, G.Pennelli, On-chip Thermoelectric Devices Based on Standard Silicon Processing, Small 2405411, 2024

[2] A.Masci, E.Dimaggio, N.Neophytou, D.Narducci, G.Pennelli, Large Increase of the Thermoelectric Power Factor in Multi-barrier Nanodevices, Nano Energy 132, 110391, 2024

In this study, CoCrFeNiV high entropy alloy (HEA) thin films were successfully deposited on nickel foam substrates using a high power impulse magnetron sputtering (HiPIMS) system for application as advanced electrode materials in supercapacitors. The use of HiPIMS enabled precise control over film composition and enhanced adatom mobility, promoting uniform growth and strong adhesion of the HEA coating on the porous Ni foam surface. Comprehensive materials characterization, including morphological, structural, and compositional analyses, was conducted to understand the evolution of film microstructure during deposition and the elemental distribution across the coating. The electrochemical performance was systematically evaluated through cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. The CoCrFeNiV HEA electrode exhibited a remarkably high specific capacitance and excellent rate capability, demonstrating superior energy storage characteristics. Furthermore, long-term cyclic stability tests confirmed outstanding charge–discharge durability, highlighting the potential of HiPIMS-deposited CoCrFeNiV HEA thin films as promising electrode materials for next-generation high-performance supercapacitors.