Estimation of electrical bandgap narrowing in heavily doped p-gallium arsenide

Abstract

For device modeling, the effect of heavy doping can be described by relating the effective intrinsic carrier concentration n/sub ie/ to the intrinsic carrier concentration in lightly doped material n/sub io/ with a nonphysical apparent bandgap shrinkage. The electrical measurements on bipolar devices provide the value of the equilibrium minority-carrier concentration and cannot directly give the amount of bandgap narrowing. The aim of this work is to extract this nonphysical, apparent bandgap shrinkage from the measurement of the minority-carrier transport parameters in p/sup +/-n GaAs diodes with the p/sup +/-layer hole density in the range from 6.3*10/sup 17/ to 1.3*10/sup 19/ cm/sup -3/. The recombination velocity at the surface of the p/sup +/ layer is calculated and compared with the available experimental data. >