Reflectance Difference Spectroscopy of GaAs Asymmetric Surface Quantum Wells above the Fundamental Gap

✍ Scribed by Lastras-Martínez, L.F. ;Rönnow, D. ;Cardona, M. ;Specht, P. ;Santos, P.V. ;Eberl, K.

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 154 KB
• Volume: 170
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/(sici)1521-396x(199812)170:2<317::aid-pssa317>3.0.co;2-v

✦ Synopsis

We report Reflectance Difference (RD) measurements on (001) GaAs surface quantum wells (QW) under Ultra High Vacuum (UHV) conditions from 1X7 to 5X0 eV. The QW is embedded between an arsenic-rich reconstructed GaAs surface and an AlAs barrier. The samples, grown by MBE with a protective arsenic cap layer, were heated to 320 and 430 C to desorb the As layer and form c4 Â 4 and 2 Â 4 surface reconstructions, respectively. By modifying the surface reconstruction, we are able to separate the contributions to the optical anisotropy from the surface region (mainly associated with the As dimers) from those originating below the surface.