Dresden 2006 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 47: GaN: Devices II

HL 47.3: Vortrag

Donnerstag, 30. März 2006, 15:45–16:00, BEY 118

Study and comparison of efficiency and optical degradation of GaN/InGaN Light Emitting Diodes grown on SiC substrates — •Gianluca Tamiazzo, Ulrich Zehnder, Thomas Zahner, and Uwe Strauss — Wernerwerkstrasse 2, 93049 Regensburg

High reliability of GaN/InGaN based Light Emitting Diodes (LEDs) is of great interest. However, despite of high long-term stability, degradation mechanisms could potentially occur. In this work, we study GaN/InGaN LEDs structures for a further improvement of their reliability and lifetime. A comparison with other commercial devices coming from different competitors was performed as well. The samples were biased in identical conditions of temperature and injected current. Electroluminescence relative intensity of LEDs was monitored in dependence of time. Dynamics of optical degradation as well as forward voltage aging during the DC-bias stress were studied. Different aging phases correspondent to as many potential failure mechanisms were identified. A model able to interpret the devices degradation behaviour is proposed. In particular, a thermally activated process is found to be responsible for long-term DC aging.