Electrophysical properties and structural evolution under the influence of external factors of nanocrystalline molybdenum films as sensor electronics elements

The paper presents the results of studies on the electrophysical properties (electrical resistance, temperature coefficient of resistance, strain sensitivity) and structural evolution of nanocrystalline molybdenum films (nc-Mo) under the influence of external factors (gas adsorption, heat treatment, mechanical deformation). A comprehensive approach to controlling the structural–phase state of the films is proposed, which makes it possible to regulate their functional characteristics and predict operating parameters. The study investigates the electrophysical, structural, and mechanical properties of nanocrystalline molybdenum films (nc-Mo) obtained by physical vapor deposition (PVD). The dependence of structural modifications and phase transition temperatures on deposition conditions has been established, and phase transformations with the formation of metastable oxide and carbide compounds on the film surfaces have been revealed. The presence of oxide and impurity phases was confirmed by Fourier Transform Infrared Spectroscopy (FTIR). Electrical measurements showed that the increase in the resistivity of nc-Mo films is caused by electron scattering at surfaces and grain boundaries, with the average electron mean free path being 11.0 nm and the reflection coefficient of conduction electrons at grain boundaries being R = 0.47. Mechanical tests revealed a strain coefficient SC ≈ 4 under 1–2 % longitudinal quasi-elastic deformation. The temperature coefficient of resistance (TCR) ≈ 0.25·10⁻³ K⁻¹ in the temperature range 300–750 K. The obtained results indicate the potential of using nc-Mo films as materials for sensor, accessible and clean energy systems, as well as for metallization elements in microchips.