Effective Thermal Management in Ultraviolet Light-Emitting Diodes With Micro-LED Arrays

N. Lobo Ploch1, H. Rodriguez2, C. Stölmacker2, M. Hoppe2, M. Lapeyrade2, J. Stellmach1, F. Mehnke1, T. Wernicke1, A. Knauer2, V. Kueller2, M. Weyers2, S. Einfeldt2, and M. Kneissl1,2

Published in:

IEEE Trans. Electron Devices, vol. 60, no. 2, pp. 782-786 (2013).

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Abstract:

We report on the use of micro-LED arrays, consisting of a matrix of interconnected micrometer-size light-emitting diodes (LEDs), to ensure uniform current injection, reduced series resistance, and improved heat extraction in LEDs emitting in the ultraviolet wavelength region. With the help of experiments and simulations, we show that, in both 380- and 300- to 325-nm LEDs, a greater than twofold decrease in the thermal resistance of the device, as compared with a conventional large area contact, is possible with the use of micro-LED arrays. The thermal resistance was found to linearly decrease with the size of the individual micro- LED, indicating that the improved heat dissipation is mainly due to the division of the heat source from one large area for the square contact into smaller pixels, thus allowing a sufficient area for the dissipation of the generated heat.

1 Institute of Solid State Physics, Technical University of Berlin, 10623 Berlin, Germany
2 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, D-12489 Berlin, Germany

Index Terms:

InAlGaN, micro-LED arrays, thermal management, ultraviolet (UV) light-emitting diodes (LEDs).