Improved AlGaInP vertical emitting light-emitting diodes using direct printing.

In this study, we fabricated a high-brightness AlGaInP light-emitting diode (LED) using the direct printing technique and dry etching. In general, wet etching is used for surface roughening to improve the light extraction of AlGaInP red LEDs. However, a structure fabricated by wet etching has limited height and shows a tiled cone shape after the etching process due to the AlGaInP crystal structure. These limitations reduce the light extraction of the LED. As a result, we fabricated a perfectly cone-shaped pattern with high aspect ratio using direct printing by etching to maximize the LED light extraction efficiency. Compared to the red LED with a wet-etched structure, the patterning enhanced the light output power by 12% without electrical degradation. This enhanced light output power was maintained even after the packaging process.