Oscillator Strength of Excitons in InGaAs/GaAs Quantum Wells

The oscillator strength of excitons in InGaAs/GaAs single quantum wells is studied for the first time by reflectance measurements using a Fourier transform spectrometer. Decrease of the oscillator strength of the zero phonon line at higher temperatures is found and analyzed using the temperature dependence of a modified Debye-Waller factor with an averaged phonon mode. For a sample of X=140Å, the oscillator strength is estimated to be 5.1 x 10-4 Å-2. The well width dependence of the oscillator strength is found to reach a maximum at a critical well width. We also observe anomalies in the oscillator strength and linewidth at temperatures lower than 50 K. © 1993, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.