Space-charge-controlled conductivity in low-density polyethylene

We studied the dc conductivity of low-density polyethylene in the temperature range from 20 to 90 °C for electric fields from 4 kV m−1 to 20 MV m−1. The isochronal data measured after 1 h are in agreement with the literature. For a long time (6 days), the conduction mechanism is dominated by the spa...

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Bibliographic Details
Published in:Applied physics letters 2003-03, Vol.82 (12), p.1920-1922
Main Authors: Neagu, Eugen R., Marat-Mendes, Jose N.
Format: Article
Language:English
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Summary:We studied the dc conductivity of low-density polyethylene in the temperature range from 20 to 90 °C for electric fields from 4 kV m−1 to 20 MV m−1. The isochronal data measured after 1 h are in agreement with the literature. For a long time (6 days), the conduction mechanism is dominated by the space charge trapped in the material. The current does not attain a steady-state value after 29 days at 50 °C and 8 MV m−1. It oscillates continuously, the variations are less regular and the conductivity decreases significantly as the sample thickness increases. The activation energy decreases from 0.8 to 0.58 eV when determined from long time measurements. An explanation is proposed considering the constraints imposed by the trapped space charge on charge injection and transport. We propose to call the observed mechanism space-charge-controlled conductivity.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.1559656