The optical energy gap dependence on both carrier concentration and intrinsic energy gap in n-type semiconductors

Burstein and Moss formulas were used to calculate the optical energy gaps for five n-type compound semiconductors. The room-temperature intrinsic energy gaps were found to increase from 2% for ZnO to about 7 times of its value for InSb. The room temperature critical Burstein point of carrier concentration nmnm for five compounds of InSb, InAs, GaAs, CdO and ZnO were found to be 0.27×1018, 0.67×1018, 3.0×1018, 8.5×1018 and 20×1018 cm−3, respectively and the empirical relation Egi=4×10−13×(nm)0.6737 was found, where nm in cm−3 and Egi in eV. The latter relation gives the room temperature intrinsic energy gap for the compounds InP, GaSb and CdGeAs2 to be 1.18 eV, 0.75 eV and 0.45 eV, respectively.A general empirical relation was also found for the dependence of the change of the optical energy gap of semiconductors on both their intrinsic energy gap and their carrier concentration.