Polycrystalline Niobium-Based Transparent Conductors as ITO Alternatives
Johnny AZZI
Monday, May 4, 2026 at 1:00 p.m.
Abstract:
Indium tin oxide (ITO), the industry-standard transparent conductor, faces critical limitations including indium scarcity, high production costs, and brittleness. Despite extensive research into alternative materials such as tin oxide (SnO₂), aluminum-doped zinc oxide (AZO), and fluorine-doped tin oxide (FTO), none have successfully dethroned ITO due to inferior optoelectronic properties, lower thermal stability, or increased processing complexity. Recent literature has demonstrated that strontium niobate (SrNbO₃, SNO) surpasses ITO in optoelectronic properties; however, these results are limited to epitaxial thin films requiring secondary vacuum conditions and elevated deposition temperatures, which severely hamper industrial scalability.
This thesis explores polycrystalline and amorphous SNO films synthesized via chemical vapor deposition (CVD) under primary vacuum conditions—an approach never previously reported in the literature. We employ a novel chemical strategy combining metallic element reduction with cation deficiency engineering, wherein the Sr/Nb ratio is deliberately reduced to modulate the Nb⁵⁺/Nb⁴⁺ oxidation state and optimize electrical conductivity without external doping. This relaxed vacuum requirement enables low-temperature processing while eliminating epitaxial substrate constraints, significantly enhancing scalability for industrial implementation.Indium tin oxide (ITO), the industry-standard transparent conductor, faces critical limitations including indium scarcity, high production costs, and brittleness. Despite extensive research into alternative materials such as tin oxide (SnO₂), aluminum-doped zinc oxide (AZO), and fluorine-doped tin oxide (FTO), none have successfully dethroned ITO due to inferior optoelectronic properties, lower thermal stability, or increased processing complexity. Recent literature has demonstrated that strontium niobate (SrNbO₃, SNO) surpasses ITO in optoelectronic properties; however, these results are limited to epitaxial thin films requiring secondary vacuum conditions and elevated deposition temperatures, which severely hamper industrial scalability.
The thesis presents comprehensive structural, compositional, and optoelectronic characterization of SNO thin films synthesized via primary vacuum CVD with optimized cation stoichiometry, demonstrating the viability of non-epitaxial SNO as a scalable, high-performance transparent conductor for next-generation photovoltaic and optoelectronic devices.
Date infos
Tuesday, May 26, 2026, at 1:00 p.m.Location infos
BELLEDONNE room & VIDEOCONFERENCE