High Efficiency InGaN Blue Light-Emitting Diode With ${>}{\rm 4}\hbox{-}{\rm W}$ Output Power at 3 A

This letter reports high-power and high-efficiency characteristics of the InGaN-based blue light-emitting diode (LED) operating at > 10-W electrical input power in a single-chip package. The LED chip is fabricated as a vertical-injection structure with chip dimensions of 1.8 mm × 1.8 mm. InGaN/GaN short-period superlattice (SL) structures are employed below multiple-quantum-well active region as current spreading layers. It is found, by simulation, that SL layers are quite effective in improving current spreading and uniformity in carrier distribution. When the characteristics of the fabricated LED package are measured under pulsed operation conditions, efficiency droop is found to be greatly reduced in the LED structure with SL layers. A record high light output power of 4.18 W and external quantum efficiency of 51% are demonstrated at 3-A injection current.