Sensors and Electron Devices Directorate Research Areas

Physics and Chemistry of Organic and Inorganic Luminescent Materials

Advisor: Morton, David C. (david.morton1@us.army.mil 301-394-1916)
Keywords: Luminescence; Electronic displays; Doped crystals; Inorganic; Organic

Organic and inorganic luminescent materials are utilized in various display devices. Therefore, it is essential that we explore their optical, chemical, crystallographic, and electrical properties from a basic research viewpoint. For inorganic devices, we are interested in doping studies and characterization of wide band gap (WBG) materials and devices to establish donor/acceptor levels in the forbidden gap. The materiel properties such as crystallinity, film morphology, and doping concentration are correlated to device characteristics under different excitation types (i.e., cathode ray, electric field, photons). In addition, the carrier transport in these structures and devices is a key area of investigation. Another interest area includes identifying and assessing the physical effect of defects in the materials on the luminescent excitation and relaxation processes. For organic based devices, we are interested in similar material and device properties, including organic film formation, doping, carrier transport, and molecular structure. Cooperative research for both organic and inorganic device physics is being carried out with several universities on different materials, structures, and devices. In house, we have several deposition systems for thin-film device fabrication that include inorganic phosphors, dielectrics, and metals as well as systems dedicated to organic device fabrication, and for high-process temperature phosphor powder investigations. The laboratory is equipped with many characterization capabilities to study the material and device properties as a function of temperature from 10 K to 800 K. These techniques include pulsed and DC current-voltage characterization, trap state spectroscopy, Raman, AFM, Fourier-transform infrared, photoluminescence (DC to 2nsecs), electroluminescence, cathodoluminescence and others. This research will be done in collaboration with the microanalysis group at SEDD to provide the other materials characterization capabilities.