Suppression of damage to organic light-emitting layers during deposition of Al-doped ZnO thin films by radio-frequency magnetron sputtering

Conditions for deposition of Al-doped ZnO (AZO) films on an organic light-emitting layer with a radio-frequency magnetron sputtering system were optimized to realize high deposition rate and low resistivity of the films. Damage inflicted on the organic layer by depositing the AZO film under the optimized deposition conditions was studied from photoluminescence, UV-Vis and Fourier transform infrared spectroscopy spectra using tris(8-hydroxyquinolinato)aluminium as a model organic compound. We found that damage to the organic layer was lessened by increasing the magnetic field from a normal intensity of 0.02 T to 0.1 T. The damage to the organic layer was further lessened by inserting a grounded grid electrode between a target and the substrate.