The superlattice barrier capacitor: A structure for the investigation of heterojunction interfaces

A symmetric n- GaAs/AlAs-GaAs superlattice/n- GaAs structure has been fabricated and electrical measurements made between 300 and 77 K. At 238 K and below, the C-V characteristics were clearly symmetric, in good agreement with theory. Such a structure can be used as a sensitive probe of the interface defects at the "normal" and "inverted" heterojunction interfaces associated with the barrier. Furthermore, the highly nonlinear C-V characteristic of this symmetric semiconductor capacitor near-zero bias may have unique applications.