Transmission tunneling current across heterojunction barriers

The tunneling current across an isotype n GaAs/AlGaAs heterojunction is calculated by solving the Schrodinger equation for a stepwise approximation of the potential energy. The influence on the calculated current of different potential energy approximations is considered. Results of the model are compared with those of the thermionic model and with experimental data. It is found that the thermionic model tends to underestimate the current, especially when very thin barriers are considered as in the case of high reverse voltages. An oscillatory behavior of the transmission probability due to resonance through virtual states above the barrier, induced by potential energy discretization, is found. Reducing the number of layers in the potential energy approximation leads to higher oscillation and inaccurate results for the tunneling current