TY - JOUR
T1 - Use of graphene for forming Al-based p-type reflectors for near ultraviolet InGaN/AlGaN-based light-emitting diode
AU - Kim, Dae Hyun
AU - Han, Jaecheon
AU - Seong, Tae Yeon
PY - 2014/1/1
Y1 - 2014/1/1
N2 - 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 × 10-3 Ωcm 2 than the ITO/Al contact (with 9.5 × 10-3 Ωcm2). 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.
AB - 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 × 10-3 Ωcm 2 than the ITO/Al contact (with 9.5 × 10-3 Ωcm2). 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.
KW - Graphene
KW - ITO/Al
KW - Reflector
KW - UV light emitting diode
UR - http://www.scopus.com/inward/record.url?scp=84904280435&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84904280435&partnerID=8YFLogxK
U2 - 10.1016/j.cap.2014.06.012
DO - 10.1016/j.cap.2014.06.012
M3 - Article
AN - SCOPUS:84904280435
VL - 14
SP - 1176
EP - 1180
JO - Current Applied Physics
JF - Current Applied Physics
SN - 1567-1739
IS - 9
ER -