Improvement of light extraction efficiency in InGaN/GaN-based light-emitting diodes with a nano-roughened p-GaN surface

The following paper presents a study on the performance of InGaN/GaN-based light-emitting diodes (LEDs) with a nano-roughened p-GaN surface, which were grown by metal-organic chemical vapor deposition. This nano-roughened p-GaN surface was obtained by using nitrogen (N-2) as cyclopentadienyl magnesium (Cp2Mg) carrier gas during the growth of p-GaN layer. Research results show that the surface roughness of p-GaN layer is influenced by the injection flow of N-2 and the injection time of N-2. Under the optimal process condition, the light output power of LED with a nano-roughened p-GaN surface is improved by 30.4 % compared with that of conventional LED with an injection current of 20 mA. Meanwhile, current-voltage curve shows that the electrical performance of this sample is similar to that of conventional LED. The improvement of light output power is mainly attributed to the higher light extraction efficiency when nano-roughened p-GaN surface is adopted.