ELECTRIC-FIELD DOMAINS IN SEMICONDUCTOR SUPERLATTICES - RESONANT AND NONRESONANT TUNNELING

Photoluminescence experiments detecting the occupation of higher subba nds in GaAs-AlxGa1-xAs superlattices are used to determine the field s trengths of electric-field domains. While the magnitude of the electri c field in the low-field domain corresponds to resonant alignment of s ubbands in adjacent wells, the field strength in the high-field domain is below the value corresponding to the resonant field. These results are interpreted in terms of a simple model based on current conservat ion.