Solubility Range, Lattice Constant and Energy Band Gap of a New Quaternary Solid Solution Semiconductor Pb1-xMgxSi1-ySey for Mid-Infrared Laser

We have investigated a new quaternary solid solution semiconductor Pb1-x Mg x S1-y Se y in bulk substance. The solubility limits of Mg in Pb1-x Mg x S1-y Se y system were varied from 0.03 to 0.07 under the fixed composition y at 1000 °C, and the typical limit of Mg in the system was 0.05 in Pb1-x Mg x S ternary solid solution. The lattice constants of Pb1-x Mg x S1-y Se y solid solution were changed from 5.922 to 6.120 Å. The relation between the lattice constant L and the composition x in Pb1-x Mg x S ternary solid solution was expressed as L=5.936-0.320x (x≦0.05). The energy band gaps were linearly increased in proportion to the Mg concentration x within the solubility range, and the relation between the energy band gap E g and the composition x in Pb1-x Mg x S ternary solid solution was expressed as E g =0.42+1.23x+3.75x 2 (x≦0.05).