Simulation of electron beam induced current at GaAs/AlGaAs heterojunctions under forward bias

Abstract

The influence of the charge collecting barrier on the electron beam induced current (EBIC) is studied by numerical solution of the current transport equations in the case of AlGaAs/GaAs heterojunctions. EBIC line scans are simulated as a function of external bias. It is found that the signal cannot be reduced to zero value, in accordance with experimental results. This effect is explained by a non-negligible potential drop outside of the space-charge region under high injection conditions. As a consequence, a more careful treatment is needed when using EBIC to determine band offsets.