Use of graphene for forming Al-based p-type reflectors for near ultraviolet InGaN/AlGaN-based light-emitting diode

다국어 초록 (Multilingual Abstract)

We demonstrated the improved performance of near UV (365 nm) InGaN/AlGaN-based LEDs using highly reflective Al-based p-type reflectors with graphene sheets as a diffusion barrier. The use of graphene sheets did not degrade the reflectance of ITO/Al contacts, viz. ~81% at 365 nm. The ITO/graphene/Al contacts annealed at 300 C exhibited better ohmic behavior with a specific contact resistance of 1.5 103 Ucm2 than the ITO/Al contact (with 9.5 103 Ucm2). Near UV LEDs fabricated with the ITO/ graphene/Al contact annealed at 300 C showed a 7.2% higher light output (at 0.1 W) than LEDs with the ITO/Al reflector annealed at 300 C. The SIMS results exhibited that, unlike the ITO/graphene/Al, the ITO/ Al contacts undergo a significant indiffusion of Al atoms toward the GaN after annealing. Furthermore, both Ga and Mg atoms were also more extensively outdiffused in the ITO/Al contacts after annealing. On the basis of the SIMS and electrical results, the possible explanations for the annealing-induced degradation of the ITO/Al contacts are described and discussed.

참고문헌 (Reference)

• 1 W. Sun, 43 : L1419-, 2004
• 2 K. Hattori, 53 : 6906-, 1982
• 3 H. Tsuzuki, 311 : 2860-, 2009
• 4 M. Khizar, 86 : 173504-, 2005
• 5 H. -G. Hong, 88 : 103505-, 2006
• 6 T. N. Oder, 84 : 466-, 2004
• 7 J.-Y. Kim, 15 : H198-, 2012
• 8 H. Kim, 9 : 336-, 2007
• 9 T. Jeong, 47 : 8811-, 2008
• 10 N. Lobo, 96 : 081109-, 2010
• 11 K. Takehara, 51 : 042101-, 2012
• 12 P. Lange, 115 : 23057-, 2011
• 13 S. Chen, 5 : 1321-, 2011
• 14 A. C. Ferrari, 97 : 187401-, 2006
• 15 K. N. Kudin, 8 : 36-, 2008
• 16 J. -O. Song, 86 : 133503-, 2005
• 17 W. H. Lee, 47 : 1277-, 2011
• 18 S.Y. Kim, 7 : G102-, 2004
• 19 J. -O. Song, 85 : 6374-, 2004
• 20 J. H. Son, 33 : 2907-, 2008
• 21 M. E. Lin, 64 : 1003-, 1994
• 22 J. O. Song, 80 : 3128-, 2002
• 23 B. P. Luther, 13 : 1322-, 1998
• 24 B. P. Luther, 71 : 3859-, 1997
• 25 M. Kneissl, 45 : 3905-, 2006