Humidity as a critical parameter for predicting breakdown voltage in submicrometer electrode gaps in air
B Disson1, N Bonifaci2, O Lesaint2
1Université d'Orléans, CNRS, GREMI (Groupe de Recherches sur l'Énergétique des Milieux Ionisés), UMR7344 , 14 rue d'Issoudun, 45067 Orléans, France.
Physical Review. E
|July 24, 2026
Summary
Humidity significantly impacts microgap breakdown voltage, unexpectedly reducing it in air unlike in larger discharges. This study reveals key mechanisms and questions prior research lacking humidity data.
Area of Science:
- Physics
- Electrical Engineering
- Materials Science
Background:
- Paschen's law typically describes breakdown voltage in gases.
- Microgap discharges exhibit complex behaviors not fully explained by existing laws.
- Humidity's role in microgap breakdown is under-investigated and poorly understood.
Purpose of the Study:
- To experimentally investigate breakdown voltage in air for microelectrode gaps (0.10–6.00µm).
- To specifically analyze the impact of varying gas humidity on breakdown voltage.
- To elucidate the mechanisms driving breakdown in microgaps under different humidity conditions.
Main Methods:
- Experimental measurements of breakdown voltage across a range of electrode gaps.
- Systematic variation of air humidity (dew point) while keeping other parameters constant.
- Statistical analysis to identify breakdown mechanisms (Field Emission and Townsend Avalanche).
Main Results:
- Breakdown voltage deviates from Paschen's law in microgaps (<2µm), showing a linear increase.
- In dry air, breakdown mechanisms resemble those in argon, with Field Emission occurring at ~0.86V/nm.
- Increased humidity drastically reduces breakdown voltage in microgaps, contrary to macroscopic discharge behavior.
Conclusions:
- Humidity plays a critical, counterintuitive role in microgap breakdown voltage.
- Water molecules and electrode surface effects significantly influence breakdown mechanisms.
- Humidity conditions must be documented in future microgap discharge research to ensure result validity.
Related Concept Videos
01:30The Electrical Double Layer
In the region where two bulk phases meet, an intricate electric charge distribution arises due to charge transfer, ion adsorption, molecular orientation, and charge distortion. This complex distribution is commonly referred to as the electrical double layer.When a solid electrode interfaces with ions in an electrolyte solution, the speed of electron transfer dictates the rates of oxidation and reduction. The electrode acquires a charge through the escape of atoms into the solution as cations or...
01:30Processes at Electrodes
The electrode interacts with ions in the electrolyte solution at its interface. The rate of oxidation and reduction depends on the speed at which electrons can transfer through this interface. As ions attach to or leave the electrode surface, the electrode acquires a charge, and an electrical potential forms across the interface, making the process more difficult to reach equilibrium. The charge on the electrode affects the local ion concentrations in the solution, though thermal motion...