Oscillator Strengths for Neutral, Charged, and Scattered Excitons in CdTe Quantum Wells Containing a 2D Electron Gas

R.T. Coxa, V. Huarda, C. Bourgognona, K. Saminadayara, S. Tatarenkoa and R.B. Millerb aEquipe "Nanophysique et Semiconducteurs" de SP2M, CEA-Grenoble et du Laboratoire de Spectrométrie Physique, Université Joseph Fourier, 38054 Grenoble-Cedex, France bDepartment of Physics, La Trobe University, Victoria 3086, Australia

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Received: 10 06 2004

Absorption spectra have been measured for a 10 nm CdTe(0.3%Mn) quantum well with electron concentration ne variable up to 1.5×1011cm-2 Following recent theory appropriate to low ne, here ≈0.1/π αB2, the spectra are interpreted in a "strong exciton" model, where the initial oscillator strength of the excitonic resonance (X) is conserved, with screening and phase-space filling effects negligible. As ne increases in zero-field and as the filling factorν increases in magnetic field, the intensity of X is transferred to: (i) trion processes, namely exciton-one electron scattering and the trion resonance (T), and (ii) quatron processes, namely exciton-two electron scattering and trion-one electron scattering. In magnetic field, the three- and four-body scattering processes become discrete, combined "exciton and cyclotron" and combined "trion and cyclotron" excitations that take all the intensity of X and T for ν≾1 and ν>2, respectively.

DOI: 10.12693/APhysPolA.106.287 PACS numbers: 78.30.Fs, 78.67.De, 78.40.Fy, 78.55.Et