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Proceedings Paper

Changes in the Mg profile and in dislocations induced by high temperature annealing of blue LEDs
Author(s): M. Meneghini; N. Trivellin; M. Berti; T. Cesca; A. Gasparotto; A. Vinattieri; F. Bogani; D. Zhu; C. J. Humphreys; G. Meneghesso; E. Zanoni
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Paper Abstract

The efficiency of the injection and recombination processes in InGaN/GaN LEDs is governed by the properties of the active region of the devices, which strongly depend on the conditions used for the growth of the epitaxial material. To improve device quality, it is very important to understand how the high temperatures used during the growth process can modify the quality of the epitaxial material. With this paper we present a study of the modifications in the properties of InGaN/GaN LED structures induced by high temperature annealing: thermal stress tests were carried out at 900 °C, in nitrogen atmosphere, on selected samples. The efficiency and the recombination dynamics were evaluated by photoluminescence measurements (both integrated and time-resolved), while the properties of the epitaxial material were studied by Secondary Ion Mass Spectroscopy (SIMS) and Rutherford Backscattering (RBS) channeling measurements. Results indicate that exposure to high temperatures may lead to: (i) a significant increase in the photoluminescence efficiency of the devices; (ii) a decrease in the parasitic emission bands located between 380 nm and 400 nm; (iii) an increase in carrier lifetime, as detected by time-resolved photoluminescence measurements. The increase in device efficiency is tentatively ascribed to an improvement in the crystallographic quality of the samples.

Paper Details

Date Published: 27 March 2013
PDF: 7 pages
Proc. SPIE 8625, Gallium Nitride Materials and Devices VIII, 86251P (27 March 2013); doi: 10.1117/12.2003542
Show Author Affiliations
M. Meneghini, Univ. degli Studi di Padova (Italy)
N. Trivellin, Univ. degli Studi di Padova (Italy)
M. Berti, Univ. degli Studi di Padova (Italy)
T. Cesca, Univ. degli Studi di Padova (Italy)
A. Gasparotto, Univ. degli Studi di Padova (Italy)
A. Vinattieri, Univ. degli Studi di Firenze (Italy)
F. Bogani, Univ. degli Studi di Firenze (Italy)
D. Zhu, The Univ. of Cambridge (United Kingdom)
C. J. Humphreys, The Univ. of Cambridge (United Kingdom)
G. Meneghesso, Univ. degli Studi di Padova (Italy)
E. Zanoni, Univ. degli Studi di Padova (Italy)


Published in SPIE Proceedings Vol. 8625:
Gallium Nitride Materials and Devices VIII
Jen-Inn Chyi; Yasushi Nanishi; Hadis Morkoç; Joachim Piprek; Euijoon Yoon; Hiroshi Fujioka, Editor(s)

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