Specific Features of Carrier Transport in n + – n 0 – n + Structures with a GaAs/AlGaAs Heterojunction at Ultrahigh Current Densities

The current–voltage characteristics of n + -GaAs/ n 0 -GaAs/ N 0 -AlGaAs/ N + -AlGaAs/ n + -GaAs isotype heterostructures and n + -GaAs/ n 0 -GaAs/ n + -GaAs homostructures are studied. It is shown that, for a heterostructure under reverse bias providing the injection of electrons from n 0 -GaAs into N 0 -AlGaAs, the maximum operating voltage reaches a value of 48 V at a thickness of the N 0 -AlGaAs layer of 1 . 0 μm, and the current–voltage characteristic has no region of negative differential resistance. The operation of a homostructure is accompanied by a transition to the negative-differential-resistance region at a voltage of 10 V. Theoretical analysis in terms of the energy-balance model demonstrated that the reverse-biased isotype heterostructure has no negative-differential-resistance region because, in this case, the field domain does not collapse in contrast to what occurs in homostructures.