Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 25: Poster Session: GaN - Optical Properties & Preparation and Characterization & Devices
HL 25.11: Poster
Montag, 26. März 2012, 16:00–19:00, Poster D
Photoluminescence line shape features of carbon delta-doped GaAs heterostructures — Jürgen Schuster1, •Tae Yang Kim1, Edwin Batke1, Dirk Reuter2, and Andreas Wieck2 — 1Physikalisches Institut der Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany — 2Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstrasse 150, D-44780 Bochum, Germany
The PL line shape properties of quasi two-dimensional electron gas (2DEG) in setback delta doped GaAs heterostructure at liquid helium temperature are studied. We illuminated the sample with two different excitation energies, below and above the band gap of AlGaAs. The whole density of states of 2DEG can be directly visible due to the relaxation of k-selection rule. We observed clearly the ground and the first excited 2D subbands. A simple fit to the line shape including broadening demonstrated that there is an exponential low-energy tail associated with the ground subband. The fit precisely reveals the subband bottom energies, the quasi Fermi-energy, the electron temperature and the integrated strengths, enabling an accurate determination of the subband populations and the transition probability. A self-consistent calculation of subband properties including the potential contribution of the delta doping reproduces the subband separations and recombination intensities well. The dependence of excitation intensity, temperature and magnetic field strength on the PL line shape is studied.