This one is interesting too!
Quote:
"United Epitaxy Company has released a 10-Watt AlGaInP high-power LED made using a proprietary "metal bonding" technique. The LED is grown on a GaAs substrate, with a grid-pattern ohmic contact metal layer and a high-reflectivity metal layer deposited on top of the LED epiwafer. The metal layers of the LED epiwafer are then bonded to a silicon substrate and the GaAs substrate is removed, leaving a diode consisting of a silicon substrate soldered to the metal layers, overlain by the AlGaInP LED wafer. The output of these "metal bonded" AlGaInP on-silicon LEDs increases linearly with drive current up to 5 A. The total flux from a single 2.5 x 2.5 square mm emitter is more than 200 lm at 12 W input power, with luminous efficiencies around 18 lm/W. Compared to AlGaInP-on-GaAs LEDs, metal bonded AlGaInP-on-silicon LEDs are twice as bright at 150 mA due to their greater heat dissipation and light extraction capabilities. [ Article in CompoundSemiconductor.net – page 1, page 2 ]"