Resistance switching in palladium nanoscale pine-cone structures for hydrogen sensors with a focus on individual effects of hydrogen desorption and volume shrinkage in recovery states

초록

In this study, nanoscale palladium structures were fabricated by electrodeposition to elucidate the resistance switching mechanism during the response and recovery states of a hydrogen sensor. Palladium nanostructures were electrodeposited on patterned microelectrodes. Hydrogen sensing experiments were conducted at hydrogen concentrations (70 ppm to 3.5%) to investigate the resistance switching characteristics. In the response state, resistance changed through two sequential stages: hydrogen induced lattice expansion accompanied by phase transition from α to β phase, followed by electron scattering caused by adsorbed hydrogen. In the recovery state, resistance changed through three sequential stages: surface desorption, interstitial desorption, and volume shrinkage. Low concentration hydrogen tests below 1.0% revealed concentration dependent on the activation of these mechanisms, with complete phase transition confirmed at 0.4% and electron scattering onset above 0.6%. Additionally, flow variation experiments (100–500 sccm) indicate that the surface desorption stage was affected by the flow rate, confirming physical desorption. © 2026 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

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