Current-voltage characterization of doped polystyrene thin films with view to gas sensing
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Date
2004
Authors
Wafula, A. B.
Katana, G.
Journal Title
Journal ISSN
Volume Title
Publisher
Kenyatta University
Abstract
Current-voltage measurements of iodine doped polystyrene thin films as a function of dopant
concentration, temperature and radiation have been carried out. The thin films were prepared by
solution casting method taking the constituents in right proportions. All devices showed
memory arid threshold switching except for doped annealed samples that lost both memory
threshold switching at a temperature of 90°(:. The thickness was varied from 3-7/lm while the
concentration of iodine varied from 0.025 to 0.100 g. The threshold voltage was lower in pure
samples than in doped samples indicating an increase in disorder in the arrangements of the
atoms. Irradiated and annealed devices showed a marked increase in threshold voltage. Once
the pure samples switched from OFF-state to ON-state they remained in the ON state but the
doped samples returned to their original state after 33 minutes to 3 hours of switching
depending on the concentrations.
The space charge limited current theory is a suitable model to explain condition in these
polymeric materials. The ON-state was ohmic while the OFF-state obeyed Child-Langmuir
law.
Description
Article
Keywords
memory, switching, doped, polymer, polystyrene
Citation
East African Journal of Physical Sciences 5( I): 3-9 (2004)