Origin of the current oscillations in GaAs-AlGaAs tunnel junctions

This Rapid Communication reviews different interpretations provided to understand the current oscillations observed in reverse-bias GaAs-AlGaAs tunnel junctions. It is seen that the ballistic picture is contradicted by the experimental conditions. Another interpretation based on phonon-assisted tunneling appears unsatisfactory with regard to several experimental observations. An explanation based on a space-charge effect induced by phonon generation is proposed. This theoretical interpretation is in good agreement with the experiment and provides a general basis for the understanding of similar effects encountered previously in analog structures.