Optical and Thermal Analyses of Thin-Film Hexagonal Micro-Mesh Light-Emitting Diodes

– KH Li, YF Cheung, Q Zhang, and HW Choi

CCD-captured images of the (a) Lat-LED, (b) Lat-μLED, (c) TF-LED, and (d) TF-μLED operated at a bias current of 10 mA. (e) 3-D and (f) Cross-sectional emission profiles captured by confocal microscope using 20× and 50× objective lens, respectively. The scale bar on the right represents normalized light intensity.

IEEE Photonics Technology Letters, vol. 25, 4, pp. 374-377 (2013)

Vertical thin-film light-emitting diodes (LEDs) with integrated micro-mesh arrays are reported. By removing the sapphire substrate through laser lift-off, vertical current conduction becomes possible, improving current spreading capability and thus electrical properties. Compared with the as-grown device, the thin-film micro-mesh LEDs emits 61% more optical power, attributed to enhanced light extraction through the micro-mesh, evidence of which is provided by confocal imaging. At 100 mA, the enhancement factor rises to >;100% attributed to low junction temperatures due to efficient heat conduction as verified by infrared thermometric imaging.

DOI: 10.1109/LPT.2013.2238621