Subpicosecond thermalization of carriers in polar GaN/AlN quantum dots
Abstract
We investigate at room temperature the thermalization and recombination dynamics of near-resonantly photogenerated carriers in c-plane GaN/AlN wurtzite quantum dots (QDs) using time-resolved photoluminescence and non-degenerate pump–probe differential transmission. Owing to a continuous gradient in dot height, the QD ensemble exhibits a broad emission range from 3.5 to 4.5 eV. Time-resolved photoluminescence reveals two distinct recombination lifetimes associated with two families of QDs with different morphologies, whose emission energies are governed by the interplay between the quantum-confined Stark effect and lateral confinement. Pump–probe measurements evidence an ultrafast carrier thermalization with subpicosecond rise times on the order of 200 fs, significantly shorter than in other epitaxial III–V QD systems. At longer delays, the relaxation dynamics is non-exponential and strongly dependent on both carrier density and probe energy. It is reproduced by a phenomenological model based on multi-carrier scattering processes, whose efficiency progressively vanishes as the probe energy approaches the luminescence maximum, where interband recombination dominates.
Article Details
Journal Info
Journal of Applied Physics
American Institute of Physics
Authors (12)
M. Hrytsaienko
Institut de Physique et Chimie des Matériaux de Strasbourg 1 , UMR 7504 CNRS-Université de Strasbourg, 23 rue du Lœss, BP 43, F-67034 Strasbourg,
D. O. Siebadji Tchuimeni
Institut de Physique et Chimie des Matériaux de Strasbourg 1 , UMR 7504 CNRS-Université de Strasbourg, 23 rue du Lœss, BP 43, F-67034 Strasbourg,
M. Ziegler
O. Crégut
Institut de Physique et Chimie des Matériaux de Strasbourg 1 , UMR 7504 CNRS-Université de Strasbourg, 23 rue du Lœss, BP 43, F-67034 Strasbourg,
G. Schmidt
F. Bertram
Institute of Physics, Otto-von-Guericke-University Magdeburg 3 , 39106 Magdeburg,
J. Christen
Institute of Physics, Otto-von-Guericke-University Magdeburg 3 , 39106 Magdeburg,
S. Tamariz
Institute of Physics, École Polytechnique Fédérale de Lausanne, EPFL 4 , CH-1015 Lausanne,
R. Butté
Institute of Physics, École Polytechnique Fédérale de Lausanne, EPFL 4 , CH-1015 Lausanne,
N. Grandjean
Institute of Physics, École Polytechnique Fédérale de Lausanne, EPFL 4 , CH-1015 Lausanne,
P. Gilliot
Institut de Physique et Chimie des Matériaux de Strasbourg 1 , UMR 7504 CNRS-Université de Strasbourg, 23 rue du Lœss, BP 43, F-67034 Strasbourg,
M. Gallart
Institut de Physique et Chimie des Matériaux de Strasbourg 1 , UMR 7504 CNRS-Université de Strasbourg, 23 rue du Lœss, BP 43, F-67034 Strasbourg,