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The Strathprints institutional repository is a digital archive of University of Strathclyde research outputs. Strathprints provides access to thousands of Open Access research papers by University of Strathclyde researchers, including those from the School of Psychological Sciences & Health - but also papers by researchers based within the Faculties of Science, Engineering, Humanities & Social Sciences, and from the Strathclyde Business School.

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Matrix-addressable micropixellated InGaN light-emitting diodes with uniform emission and increased light output

Gong, Z. and Zhang, H.X. and Gu, Erdan and Griffin, C. and Dawson, Martin D. and Poher, V. and Kennedy, G.T. and French, P.M.W. and Neil, M.A.A. (2007) Matrix-addressable micropixellated InGaN light-emitting diodes with uniform emission and increased light output. IEEE Transactions on Electron Devices, 54 (10). pp. 2650-2658. ISSN 0018-9383

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Abstract

Micropixellated InGaN light-emitting diodes (micro- LEDs) have a wide number of potential applications in areas including microdisplays, fluorescence-based assays and microscopy, and cell micromanipulation. Here, we present fabrication and performance details of matrix-addressable micro-LED devices which show significant improvements over their earlier counterparts. Devices with 64 × 64 micropixel elements, each of them having a 16-μm-diameter emission aperture on a 50-μm pitch, have been fabricated at blue (470 nm), green (510 nm), and UV (370 nm) wavelengths, respectively. Importantly, we have adopted a scheme of running n-metal tracks adjacent to each n-GaN mesa, so that resistance variation between the devices is reduced to below 8%, in contrast to the earlier fivefold resistance variation encountered. We have also made improvements to the spreading-layer formation scheme, resulting in significant increases in output power per element, improved current handling, and reduced turn-on voltages. These devices have been combined with a computerdriven programmable driver interface operating in constantcurrent mode, and representative microdisplay outputs are presented.