Photoluminescence quantum yield in GaAs/AlAs superlattices

• Published in: Solid-state electronics 1996-01, Vol.40 (1-8), p.687-691
• Main Authors: Aaviksoo, J, Gourdon, C, Grousson, R, Lavallard, P, Planel, R
• Format: Article
• Language: English
• ISSN: 0038-1101
• DOI: 10.1016/0038-1101(95)00343-6

Accurate measurement of the internal quantum yield of photoluminescence is difficult since only a small fraction of the emitted light is collected in a luminescence experiment. We propose a novel and alternative method to measure the photoluminescence quantum yield. This method is suitable for any material grown on top of another material with a lower band gap. We use a GaAs/AlAs superlattice on a GaAs layer. The intensity of luminescence emitted by the GaAs layer when it is directly excited (excitation energy above GaAs band gap, but below the SL band gap) is compared to the intensity of luminescence emitted when it is indirectly excited by luminescence light from the superlattice. In the first approximation the internal quantum yield of the superlattice photoluminescence is obtained from the ratio of the two luminescence intensities. This simple method leads to a slight underestimation of the quantum yield, whereas usual and more complicated methods using the external quantum efficiency may lead to a large overestimation in the case of high quantum efficiency and photon recycling effects.