Electroreflectance studies of thin GaAs/AlGaAs quantum well structures with tunable 2DEG densities

✍ Scribed by R. Goldhahn; S. Shokhovets; D. Schulze; N. Stein; G. Gobsch; T.S. Cheng; M. Henini; J.M. Chamberlain

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 171 KB
• Volume: 15
• Category: Article
• ISSN: 0749-6036
• DOI: 10.1006/spmi.1994.1023

✦ Synopsis

We report the results of low-temperature electroreflectance (ER) and photoluminescence (PL) investigations on thin n-type modulation-doped GaAs/AlGaAs single quantum well structures. The density of the two-dimensional electron gas (2DEG) is varied continuously from zero to (\mathrm{N}_{\mathrm{s}} \sim 6^{*} 10^{11} \mathrm{~cm}^{-2}), using a Schottky gate, and is detected optically via the Stokes shift between the ER and PL subband transitions. For the first time, the splitting between transitions involving the first electron subband and the first heavy and light hole subbands, respectively, is studied as a function of the 2DEG density using ER spectroscopy. The results are discussed in comparison with the calculated inplane dispersion of the hole subbands. Clear evidence is given for the influence of exciton screening effects.