APPLICATION OF WIDE-GAP II-VI COMPOUNDS AS EMITTERS AND DETECTORS

Despite the successes reached with wide gap II-VI materials, there is much work to be done in improving these devices in order to increase t he lifetime. Two important points in the contest that have been invest igated in Wurzburg are an improvement of p-contacts, which are still n ot very reproducible. and a decrease of threshold current densities. W e show that the formation of Ohmic contacts based on graded ZnSe/ZnTe superlattices is dominated by a diffusion process. Based on these inve stigations proposals for alternative contacts are made. A decrease of the threshold current density of blue-green laser diodes has been achi eved by a modification of the GaAs/ZnSe interface, and values as low a s 340 A/cm(2) have been obtained for simple gain guided structures wit hout facet coating. In addition to emitters, there is a significant po tential in the application of wide gap II-VI compounds as detectors in the blue and green spectral region. We describe the first fabrication of such detectors. Although these first devices are not yet optimized : they show a quantum efficiency of several percent in tile blue. The spectral response of these devices can be quantitatively described, an d based on this understanding proposals for future improvements are ma de.