Fabrication and characterization of ACTFEL devices

The goal of this thesis is the identification and synthesis of high-luminance, primary color alternating-current thin-film electroluminescent (ACTFEL) devices. Special attention is paid to the synthesis of primary color green ACTFEL devices because of the lack of an adequate primary green ACTFEL phosphor and the dominance of green wavelengths in the response of the human eye. The sulfide materials family is the focus of this investigation of ACTFEL phosphor hosts due to its importance in the field of electroluminescence, although oxide and selenide phosphor hosts are also considered. Particular attention is paid to the coactivation of the SrS:Cu ACTFEL phosphor because of the ability to control the emission spectrum with coactivators. Green ACTFEL devices exhibiting a high-luminance, high-efficiency, saturated green color are demonstrated via the coactivation of SrS:Cu with alkali metals. In addition, Zn2GeO4:Mn is demonstrated as a potentially bright and stable ACTFEL phosphor. Finally, the "phosphor sandwich" technique of ACTFEL fabrication is presented as a means of depositing highly-stable, high-luminance ACTFEL phosphors.; The fabrication techniques presented in this thesis are subsequently employed to deposit custom ACTFEL devices for characterization studies aimed at determining fundamental physical properties of ACTFEL phosphors. A method for establishing the relative hot electron distributions inside operating ACTFEL phosphor hosts is presented. In addition, the fabrication of SrS:Cu ACTFEL devices for characterization has allowed new insight into the density and physical basis of phosphor space charge. This insight is gained by monitoring the electrical and optical characteristics of SrS:Cu ACTFEL devices coactivated with various non-isovalent impurities to assess the influence of native defects and extrinsic impurities on space charge related behavior. It is found that native sulfur vacancies are not the physical basis for dynamic space charge in SrS:Cu ACTFEL devices.