Compositional plane and properties of solid solution semiconductor Pb1-xCaxS1-ySey for mid-infrared lasers

We have investigated Pb1 - xCaxS1 - ySey solid solution semiconductor. Results obtained on bulk thermal equilibrium heat-treated samples show that the lattice constants and the energy band gaps at room temperature of the Pb1 - xCaxS1 - ySey system change, respectively, from 5.862 to 6.120 Angstrom and 0.286 to around 0.9 eV. Namely, the variation of the energy band gap suggests that the Pb1 - xCaxS1 - ySey system covers a wide wavelength range from mid-infrared to near infrared if this quaternary solid solution is used as the active layer in a laser diode. From the results obtained by high-resolution X-ray diffraction with a four-crystal monochromator, no rhombohedral distortion is formed in Pb1 - xCaxS thin films employing BaF2(1 1 1) substrate and that the quality of these films is limited by mosaicity rather than slight variations of the lattice constant. (C) 1999 Elsevier Science B.V. All rights reserved.