Phys. Rev. B 79, 245316 (2009) - Quantum confinement dependence of the energy splitting and recombination dynamics of A and B excitons in a GaN/AlGaN quantum well

Quantum confinement dependence of the energy splitting and recombination dynamics of A and B excitons in a GaN/AlGaN quantum well

F. Stokker-Cheregi, A. Vinattieri, E. Feltin, D. Simeonov, J.-F. Carlin, R. Butté, N. Grandjean, F. Sacconi, M. Povolotskyi, A. Di Carlo, and M. Gurioli

Phys. Rev. B 79, 245316 – Published 18 June 2009

Abstract

We report the observation of well-resolved A and B excitonic resonances in the reflectivity spectra of a wedged GaN/AlGaN quantum well (QW) with 5% Al content in the barriers for different well thicknesses. For the thicker well cases, the energy splitting between the A and B excitons is larger than the one found for bulk GaN. However, the A-B exciton energy splitting decreases with decreasing well thickness, accordingly to the delocalization of the electron and hole wave functions in very thin QWs, as supported by theoretical simulations. Moreover, we used time-resolved photoluminescence measurements to investigate the recombination dynamics of the two excitonic states demonstrating the existence of a thermodynamic equilibrium between the two populations at a sample temperature of 10 K.

Received 31 March 2009

DOI:https://doi.org/10.1103/PhysRevB.79.245316

©2009 American Physical Society

Authors & Affiliations

F. Stokker-Cheregi^*

Department of Lasers, NILPRP, Magurele, 077125 Bucharest, Romania

Department of Physics and LENS, University of Florence, Sesto, I-50019 Fiorentino, Italy

E. Feltin, D. Simeonov, J.-F. Carlin, R. Butté, and N. Grandjean

Institute of Quantum Electronics and Photonics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland

F. Sacconi, M. Povolotskyi, and A. Di Carlo

Department of Electronic Engineering, University of Rome “Tor Vergata,” 00133 Rome, Italy

Department of Physics and LENS, University of Florence, Sesto, I-50019 Fiorentino, Italy

^*stokker@nipne.ro

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Vol. 79, Iss. 24 — 15 June 2009

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