In-situ spectroscopic analysis of the recombination kinetics in UVB LEDs during their operation

J. Ruschel1, J. Glaab1, F. Mahler2, T. Kolbe1, S. Einfeldt1, and J.W. Tomm2

Published in:

Appl. Phys. Lett., vol. 117, no. 12, pp. 121104, DOI: 10.1063/5.0018751 (2020).

Copyright © 2020 Author(s). Published under license by AIP Publishing.
Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

Abstract:

The recombination kinetics in the quantum well (QW) active region of ultraviolet light emitting diodes have been measured in situ during device operation. Non-radiative recombination is enhanced with increasing operation time. Saturation effects allow us to estimate that the density of non-radiative recombination centers in the QW layers increases by ∼5×1015cm-3 after operation. Corresponding defects are proposed to be present in the pristine device already. The recombination kinetics after optical excitation can be controlled by an additionally applied DC. The experimental approach allows the direct comparison and quantification of the effects of optically and electrically generated non-equilibrium carriers on the QW luminescence.

1 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany
2 Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Str. 2A, 12489 Berlin, Germany

Topics:

Heterostructures, Streak cameras, Epitaxy, Quantum wells, Semiconductor device fabrication, Optical properties