High brightness GaN‐based light emitting diodes using ITO/n+‐InGaN/InGaN superlattice/n+‐GaN/p‐GaN tunneling junction

• Published in: Physica status solidi. A, Applied research Applied research, 2004-09, Vol.201 (12), p.2726-2729
• Main Authors: Lee, Suk‐Hun, Son, Hyo‐Kun, Kim, Sung‐Jae, Jeong, Hwan‐Hee, Jang, Ja‐Soon, Jung, Jong‐Jae, Lee, Sang‐Hern, Kim, Tae Hoon, Yu, Young Moon
• Format: Article
• Language: English
• Subjects: 61.10.Nz; 72.80.Ey; 78.60.Fi; 85.60.Jb
• ISSN: 0031-8965; 1521-396X
• DOI: 10.1002/pssa.200405123

Indium tin oxide (ITO) ohmic electrode was employed to enhance the optical power in tunnel junction light emitting diodes (TJ‐LEDs). The electrical and optical measurement showed that the lateral current spreading and brightness were considerably improved as compared to those of conventional p/n‐junction LEDs, leading to the reduction of the forward voltage by means of 0.1 V. The TJ structure of LEDs consists of n+‐InGaN/InGaN superlattice/n+‐GaN/p‐GaN grown a InGaN/InGaN single quantum well (SQW) on AlInN/GaN multi‐buffer. The transmittance of ITO is 90–94% on 460–520 nm spectral ranges, and the total output power of SQW LEDs is effectively increased. The forward voltage of the SQW LEDs, including the voltage drop across the reverse‐biased TJ is 3.2 V at 20 mA, while that of standard SQW LEDs with a conventional contact structure is 3.1 V at 20 mA. Furthermore, the output power of LEDs with the TJ is over 6 mW at 20 mA, while that of conventional LEDs is about 4.5 mW at 20 mA. Especially, the electrostatic discharge (ESD) value of fabricated TJ‐LED chips is –5 KV at human body conditions. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)