Field-emission–driven direct current hydrogen discharges in microgaps
1 Institute of Physics, University of Belgrade - Pregrevica 118, 11080 Zemun, Serbia
2 Department of Experimental Physics, Comenius University - Mlynski dolina F2, 84248 Bratislava, Slovakia, EU
Received: 12 July 2013
Accepted: 25 August 2013
This letter contains results of the experimental and theoretical studies of the direct current hydrogen discharges generated between two plane-parallel tungsten electrodes separated from 1 μm to 100 μm. Breakdown voltage curves and volt-ampere characteristics of the discharges are presented and discussed in order to investigate fundamental processes leading to the breakdown in microgaps. Our experimental results are in accordance with the theoretical predictions which state that Townsend phenomenology breaks down when field emission becomes the key mechanism affecting the breakdown and deforming the left-hand side of the breakdown voltage curves. Based on the measured breakdown voltage curves, the dependence of the effective yield on the electric field in microgaps has been determined. Space charge effects are also estimated and distinction between Fowler-Nordheim field emission and space charge limited current density is considered.
PACS: 52.90.+z – Other topics in physics of plasmas and electric discharges (restricted to new topics in section 52) / 52.80.Tn – Other gas discharges / 52.80.-s – Electric discharges
© EPLA, 2013