Chisinau, Republic of Moldova, June 30 - July 4, 2026 https://repository.utm.md/handle/5014/37296 2026-10-13T13:20:10Z 2026-10-13T13:20:10Z AYVAZYAN, G. KHUDAVERDYAN, S. LAKHOYAN, L. VASEASHTA, A. https://repository.utm.md/handle/5014/37329 2026-10-13T06:31:49Z 2026-01-01T00:00:00Z

Optical, electrical, and gas sensing properties of ZnO dielectric films on black silicon substrates AYVAZYAN, G.; KHUDAVERDYAN, S.; LAKHOYAN, L.; VASEASHTA, A. This work reports a detailed study of the optical, electrical, and gas sensing properties of ZnO dielectric films deposited on black silicon (b-Si) substrates. The b-Si surface was fabricated using reactive ion etching (RIE), enabling the formation of dense, high-aspect-ratio nanostructures that provide strong light trapping and a significantly increased effective surface area. ZnO dielectric films were deposited onto the nanostructured b-Si substrates using the sol–gel method, ensuring good film uniformity and conformal coverage of the textured surface. Optical characterization revealed a pronounced reduction in surface reflectance and enhanced optical absorption over a broad spectral range compared to planar silicon, resulting from the combined effects of the b-Si nanostructure and the ZnO coating. Electrical measurements demonstrated stable dielectric behavior, low leakage currents, and well-defined capacitance–voltage characteristics, indicating high-quality ZnO films and a stable ZnO/b-Si interface. Gas sensing experiments showed a strong, reversible, and reproducible response to nitrogen dioxide (NO2) at relatively low operating temperatures. The enhanced sensing performance is attributed to the high specific surface area of the RIE-fabricated b-Si, efficient adsorption of NO2 molecules on the ZnO surface, and effective charge transfer across the ZnO/b-Si heterojunction. These results demonstrate the strong synergistic effect between sol–gel-derived ZnO dielectric films and nanostructured substrate, highlighting the potential of ZnO/b-Si structures for low-power NO₂ gas sensors as well as multifunctional optoelectronic and environmental monitoring applications.

2026-01-01T00:00:00Z ASSAMADI, Chaima EL MASLOUMI, Mohamed EL ABIAD, Abdelaziz AOUAD, Hakima https://repository.utm.md/handle/5014/37328 2026-10-13T06:29:52Z 2026-01-01T00:00:00Z

Structural, photocatalytic, and dielectric properties of glass-ceramics ASSAMADI, Chaima; EL MASLOUMI, Mohamed; EL ABIAD, Abdelaziz; AOUAD, Hakima Glass-ceramic materials have attracted significant interest due to their tunable structure and multifunctional properties, making them suitable for advanced technological applications. In this study, glass-ceramics were synthesized using the melt-quenching method followed by controlled heat treatment to induce crystallization. Structural investigations were carried out using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM), revealing the formation of well-dispersed crystalline phases embedded within an amorphous glassy matrix.

2026-01-01T00:00:00Z RAJI, M. https://repository.utm.md/handle/5014/37327 2026-10-13T06:27:56Z 2026-01-01T00:00:00Z

Dielectric Nanoparticles for EMI shielding applications RAJI, M. The rapid growth of electronic devices, wireless communication systems, and high-frequency technologies has significantly increased electromagnetic radiation in modern environments, leading to serious electromagnetic interference (EMI) challenges. EMI can disrupt electronic systems, decrease device reliability, and weaken communication networks. As a result, developing efficient, lightweight, and sustainable EMI shielding materials has become a key research focus. While conventional metallic shields provide high electrical conductivity and strong reflection-based shielding, they also have disadvantages, including high density, corrosion susceptibility, and limited design flexibility.

2026-01-01T00:00:00Z CAZAC, Veronica LOSMANSCHII, Constantin BOTNARI, Vladislav ABASHKIN, Vladimir ACHIMOVA, Elena https://repository.utm.md/handle/5014/37326 2026-10-13T06:26:19Z 2026-01-01T00:00:00Z

Quantitative phase imaging by all-fiber polarized digital holographic microscopy CAZAC, Veronica; LOSMANSCHII, Constantin; BOTNARI, Vladislav; ABASHKIN, Vladimir; ACHIMOVA, Elena In this work, we present an optical fiber-based polarized digital holographic microscopy system designed to improve interferometric stability and measurement precision. The proposed architecture integrates monomode optical fibers into the interferometric setup, forming a compact and robust “all-in-fiber” configuration. This approach minimizes alignment complexity and significantly reduces sensitivity to external disturbances. The system enables non-destructive, label-free imaging of transparent samples, making it particularly suitable for biological and material science applications. Dedicated software tools are developed for data acquisition and numerical reconstruction, allowing accurate phase retrieval and three-dimensional visualization. Experimental results describe the polarization calibration procedure for the developed instrument for estimating the sensitivity for quantitative birefringence measurements. The proposed FO-PDHM system represents a promising platform for advanced interferometric imaging, offering flexibility, precision, and applicability across multidisciplinary research fields.

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