Electrical-optical analysis of a GaN/sapphire LED chip by considering the resistivity of the current-spreading layer
- 255 Downloads
The effects of current distribution in LED chips on the electrical potential and optical light extraction efficiency are investigated by a numerical simulation. The results show that when the resistivity of the current-spreading layer is decreased there is current-crowding near the n-contact. On the other hand, when the resistivity in the current-spreading layer increases, there is current-crowding near the p-contact. When the current is crowded near the n-contact due to less resistivity of the current-spreading layer, the input power is lower because of the smaller series resistance in the chip, and the light extraction efficiency is higher since the shadowing effect of the p-contact can be avoided. For L p = 50 μm in this study, the light extraction efficiency at ρ ITO = 0.1 × 10−3 Ω·cm is 1.4 times better than that when L p = 100 μm, even though the driving voltage is raised 1.02 times.
Keywordscurrent-spreading light-emitting diodes indium tin oxide numerical simulation light extraction efficiency
Unable to display preview. Download preview PDF.
- 1).E. F. Schubert: Light-Emitting Diodes (Cambridge University Press, Cambridge, U.K., 2006).Google Scholar
- 8).D. W. Kim, H. Y. Lee, G. Y. Yeom, and Y. J. Sung: J. Appl. Phys. 98 (2005) 053102.Google Scholar
- 9).J. K. Sheu, Y. S. Lu, M. L. Lee, W. C. Lai, C. H. Kuo, and C. J. Tun: Appl. Phys. Lett. 90 (2007) 263511.Google Scholar