Chalcopyrite Materials Model--CM2 (Electronic Structure and Transport Properties)

摘要

Electronic transport measurements are a method of obtaining quantitative data about a semiconductor material. The measurement of the conductivity and Hall mobilities and the subsequent analysis can determine the important processes limiting the materials usefulness. For the case of Cadmium Germanium Diarsenide (CGA), saturation at higher pump power in laser systems limits its usefulness as an optical parametric oscillator (OPO) and frequency doubler. The observed saturation has been attributed to inter- and intra-valence band transitions. The intent of the this program was to verify these saturation mechanisms using an appropriate model of CGA valence band structure and electronic transport properties to predict related optional absorption and saturation. Modeling the transport properties of CGA should help in an understanding of the mechanisms behind this saturation. In addition, it will assist in materials improvement programs to reduce or eliminate the process(es) resulting in the observed saturation to obtain high conversion efficiencies observed at short wavelength infrared to LWIR CO2 region. The ultimate goal will be a greater than 25% conversion efficiency with high power CO2 pumps.