THERMODYNAMIC CALCULATION OF THE DEPENDENCE OF THE WIDTH OF THE BAND-GAP ON THE COMPOSITION OF MULTICOMPONENT SOLID-SOLUTIONS BASED ON III-V COMPOUNDS

A new method for the calculation of the width of the band gap of multicomponent III-V solid solutions is based on a thermodynamic analysis of the case of direct transitions. A relationship is established between a "sag" parameter DELTA-E(g), representing the deviation of the experimental dependence from linearity, and a parameter DELTA-H representing nonideal behavior of the molar enthalpy of several solid solutions. Thermodynamic expressions are proposed for the calculation of DELTA-E(g) and of the width of the band gap of multicomponent solid solutions.