Conduction characteristics of n-InAs/n-GaAs heterojunctions with misfit dislocations

We investigated the transport properties of an n-InAs/n-GaAs heterojunction, where misfit dislocations are confined at the hetero-interface by forming a misfit dislocation network. The electric current I across the interface from n-InAs to n-GaAs was measured as a function of applied voltage V (a). I is strongly suppressed at up to V (a) & SIM; 1.0 V which is larger than the intrinsic conduction band offset between InAs and GaAs.I increases exponentially at low and high V (a) (=0.0-0.5 and 1.0-1.2 V), while the increase of I is relatively moderate at intermediate voltage V (a) (=0.5-1.0 V). We theoretically evaluated the I-V ( a ) characteristics of the n-InAs/n-GaAs heterojunction by using the thermionic-field emission model and examined the effects of the interface states due to the misfit dislocations. The comparison of the calculated results with the experimental data indicates the existence of acceptor-like interface states in the band gap of GaAs.