Optical spectroscopy of purposely disordered GaAs/AlGaAs superlattices

✍ Scribed by Eda Tuncel; Lorenzo Pavesi; Franz-Karl Reinhart

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 435 KB
• Volume: 5
• Category: Article
• ISSN: 0749-6036
• DOI: 10.1016/0749-6036(89)90309-1

✦ Synopsis

Fluorescence line narrowing and excitation spectra measurements were performed on purposely disordered short period AlGaAs/GaAs superlattices at low temperature. Coupled to the effects of the purposely introduced disorder in the vertical direction, we observe the effects of non controlled statistical fluctuations in the composition of AlGaAs barrier materials. The first type of disorder induces variat,ions in the miniband structure of the superlattice, whereas the second type induces weakly bound localized states. We experimentally show by resonant excitation the existence of states localized below the centres of the SL minibands, and extended above. From variations in the excitation intensity, we observe the saturation of localized states bound to alloy fluctuations.