Narrow-gap alloys (Pb,Sr)Se and (Pb,Eu)Se for optoelectronic devices

(Pb,Sr)Se and (Pb,Eu)Se are semiconductors with sodium chloride structure. They exhibit a direct energy gap which opens very sharply with increasing SrSe or EuSe content an the PbSe matric. This is of interest for optoelectronic applications in photodetectors (decreasing the cut-off wavelength, increasing r(0)A), injection lasers (decreasing the emission wavelength, increasing the maximum operating temperature) as well as for waveguides and cladding layers in quantum well and heterostructures in general. A detailed analysis of the optical, magnetooptical, photoelectric and photoluminescence properties of MBE-grown layers on BaF2 substrates with energy gaps up to 500 meV at temperatures between 10 K and 300 K is given. The discussion is concentrated on the following points: -Character of the near-to-edge optical transitions, influence of Coulomb interaction on the spectra, -dispersion of the refractive index and the enhancement near E-g, -differences between (Pb,Sr)Se and the dilute semimagnetic (Pb,Eu)Se, -applications in optoelectronic devices.