| Electro-optical characterization of ACTFEL devices fabricated from thin-film phosphor materials, SrS:Cu, SrS:Cu,Ag, and SrS:Mn will be presented. A comprehensive electro-optical characterization of ACTFEL devices was accomplished by designing an automated probe station system. Characterization techniques such as current-voltage (I-V), luminance-efficiency (L-eta), external charge-applied voltage (Qext-V), capacitance-voltage (C-V), internal charge-field (Qint-F), and charge-deep level transient spectroscopy (Q-DLTS) were used to study the transported charges across the different layers and interfaces of the device during the operation. A bipolar voltage waveform with 5mus rise and fall, and 30mus duration was applied to these devices at different frequencies. Conduction, polarization, relaxation, and leakage charges due to the different interfaces and layers were measured during the emission. Traps and vacancies involved in the host materials during the growth were investigated by using Q-DLTS technique in a temperature ranging from 300K to 480K. The activation energies of the traps in the band gap region of the material, as well as their concentrations and capture cross section were measured. |
