OFFSET OF THE ELECTRICAL CHARACTERISTICS OF ALTERNATING-CURRENT THIN-FILM ELECTROLUMINESCENT DEVICES

Offset is observed in the charge-voltage (Q-V) or internal charge-phos phor field (Q-F-p) characteristics of certain alternating-current thin -film electroluminescent (ACTFEL)devices. This offset arises from a di splacement along the voltage axis of a transient curve measured across a sense capacitor in the electrical characterization setup. A procedu re for adjusting this offset is proposed that allows ACTFEL devices ma nifesting offset to be meaningfully analyzed. Two possible sources of offset are deduced from simulation and are associated with an asymmetr y in the interface state energy depths at the two phosphor-insulator i nterfaces or with an asymmetry in the location of space charge generat ion in the phosphor. (C) 1996 American Institute of Physics.