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Proceedings Paper

Microscopic-scale investigation of the degradation of InGaN-based laser diodes submitted to electrical stress
Author(s): M. Meneghini; S. Carraro; G. Meneghesso; N. Trivellin; G. Mura; F. Rossi; G. Salviati; K. Holc; T. Weig; L. Schade; M. A. Karunakaran; J. Wagner; U. T. Schwarz; E. Zanoni
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Paper Abstract

This paper presents an extensive analysis of the degradation of InGaN-based laser diodes submitted to electrical stress. The analyzed devices, with emission in the violet spectral region, were submitted to constant current stress; the degradation process was monitored by means of electro-optical measurements, which indicated that stress induced an increase in the threshold current of the devices, ascribed to the generation of non-radiative defects. After stress, the (thick) top metallization was removed, and the optical behavior of the samples was characterized by microcathodoluminescence and micro-photoluminescence investigation. Results indicate that (i) stress induced a significant degradation of the efficiency of the devices under the ridge, i.e. in the region which is crossed by high current densities during ageing. (ii) the darkening of the ridge was detected both by micro-cathodoluminescence measurements (in which carriers are generated both in the barriers and in the quantum wells) and by micro-photoluminescence analysis with subbandgap excitation (with respect to the barriers). The experimental evidence collected within this paper demonstrates that the degradation of the laser diodes can be ascribed to an increase in the rate of non-radiative recombination within the active region of the devices, possibly due to a defect diffusion process. Hypothesis on the nature of the defects involved in the degradation process are formulated based on capacitance Deep Level Transient Spectroscopy measurements.

Paper Details

Date Published: 8 March 2014
PDF: 7 pages
Proc. SPIE 8986, Gallium Nitride Materials and Devices IX, 89861P (8 March 2014); doi: 10.1117/12.2039646
Show Author Affiliations
M. Meneghini, Univ. degli Studi di Padova (Italy)
S. Carraro, Univ. degli Studi di Padova (Italy)
G. Meneghesso, Univ. degli Studi di Padova (Italy)
N. Trivellin, Univ. degli Studi di Padova (Italy)
G. Mura, Univ. of Cagliari (Italy)
F. Rossi, Istituto dei Materiali per l'Elettronica ed il Magnetismo, CNR (Italy)
G. Salviati, Istituto dei Materiali per l'Elettronica ed il Magnetismo, CNR (Italy)
K. Holc, Fraunhofer-Institut für Angewandte Festkörperphysik (Germany)
T. Weig, Fraunhofer-Institut für Angewandte Festkörperphysik (Germany)
L. Schade, Fraunhofer-Institut für Angewandte Festkörperphysik (Germany)
M. A. Karunakaran, Fraunhofer-Institut für Angewandte Festkörperphysik (Germany)
J. Wagner, Fraunhofer-Institut für Angewandte Festkörperphysik (Germany)
U. T. Schwarz, Fraunhofer-Institut für Angewandte Festkörperphysik (Germany)
Freiburg Univ. (Germany)
E. Zanoni, Univ. degli Studi di Padova (Italy)

Published in SPIE Proceedings Vol. 8986:
Gallium Nitride Materials and Devices IX
Jen-Inn Chyi; Yasushi Nanishi; Hadis Morkoç; Joachim Piprek; Euijoon Yoon; Hiroshi Fujioka, Editor(s)

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