The presence of oxygen during the deposition of the calcium electrode of polymeric light-emitting diodes is investigated. The devices are fabricated in an ultraclean setup. We used ITO as anode, OC1C10 PPV as electroluminescent polymer, calcium as cathode and aluminium as protecting layer. The influence of the presence of dry oxygen during deposition is investigated and the exposure of the calcium layer to dry oxygen subsequently to the deposition on the polymer. The change of the structure due to the exposure to oxygen is determined with elastic recoil detection analysis (ERDA) and correlated to the I-V-light characteristics of the devices. Exposure of the devices to oxygen during deposition leads to a decrease in brightness and current with increasing oxygen pressure. The exposure of the calcium to oxygen subsequently to the deposition does not affect the performance of the devices except at calcium layer thicknesses less than 10 nm.
- Elastic recoil detection analysis (ERDA)
- Organic/inorganic interfaces
- Poly(phenylene vinylene)
- Polymer light emitting diodes