Time dependence of current at high electric fields in AlxGa1¿xAs-GaAs heterojunction layers

Measurements of the current/voltage characteristics of layered xGa1¿xAs-GaAs heterostructures are presented. We show that under special circumstances surface acoustic waves can be amplified in these structures by surface acoustoelectric effects which might offer new device opportunities. In samples where the low field conduction occurs mainly in the GaAs, we observe at high fields short current peaks which we attribute to the modulation of the hot electron depletion layer width, which is consistent with the idea of real-space transfer.