Influence of the cap layer thickness on the optical properties of near surface GaInAs/GaAs quantum wells

✍ Scribed by J. Dreybrodt; F. Faller; A. Forchel; J.P. Reithmaier

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 280 KB
• Volume: 21
• Category: Article
• ISSN: 0921-5107
• DOI: 10.1016/0921-5107(93)90348-q

✦ Synopsis

We present photoluminescence investigations of GalnAs/GaAs quantum wells with thin cap layers ranging from 20 nm in thickness down to a complete cap layer removal. We observe a strong blue shift of up to 35 meV for an uncovered surface quantum well. A further shift up to the GaAs band edge can be obtained by thinning the GalnAs layer itself. To vary the cap layer thickness we used a highly diluted H:SO 4 etchant. Quantum mechanical calculations using finite cap layer thicknesses and a vacuum potential of 5 eV on the surface are in good agreement with the measured data, showing the strong influence of the vacuum potential. Furthermore, we observe a large step-like decrease in the photoluminescencc intensity at a cap layer thickness of around 10 nm.