Determination of average effective masses of majority carriers as function of impurity concentrations for heavily doped GaAs

The average effective masses of majority carriers were calculated in heavily doped n- and p-type GaAs in the impurity concentration range from 10/sup 17/ to 10/sup 20/ cm/sup -3/ at room temperature. The connection between density of states and narrowing of band gap was analyzed using kp-model. Calculated results were shown that the average effective masses of electrons and holes begin to increase for concentrations that are greater than concentrations at which Fermi levels enter the conduction band for n-type and the valence band in p-type GaAs.