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Individually-addressable flip-chip AllnGaN micropixelated light emitting diode arrays with high continuous and nanosecond output power

Zhang, H.Z. and Massoubre, D. and McKendry, J and Gong, Z. and Guilhabert, B.J.E. and Griffin, C. and Gu, E. and Jessop, P.E. and Girkin, J.M. and Dawson, M.D. (2008) Individually-addressable flip-chip AllnGaN micropixelated light emitting diode arrays with high continuous and nanosecond output power. Optics Express, 16 (13). pp. 9918-9926. ISSN 1094-4087

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Abstract

Micropixelated blue (470nm) and ultraviolet (370nm) AlInGaN light emitting diode arrays have been fabricated in flip-chip format with different pixel diameters (72μm and 30μm at, respectively, 100 and 278 pixels/mm2). Each micro-LED pixel can be individually-addressed and the devices possess a specially designed n-common contact incorporated to ensure uniform current injection and consequently uniform light emission across the array. The flip-chip micro-LEDs show, per pixel, high continuous output intensity of up to 0.55μW/μm2 (55W/cm2) at an injection current density of 10kA/cm2 and can sustain continuous injection current densities of up to 12kA/cm2 before breakdown. We also demonstrate that nanosecond pulsed output operation of these devices with per pixel onaxis average peak intensity up to 2.9μW/μm2 (corresponding to energy of 45pJ per 22ns optical pulse) can be achieved. We investigate the pertinent performance characteristics of these arrays for micro-projection applications, including the prospect of integrated optical pumping of organic semiconductor lasers.