Graphene transparent electrode for enhanced optical power and thermal stability in GaN light-emitting diodes.
We report an improvement of the optical power and thermal stability of GaN LEDs using a chemically doped graphene transparent conducting layer (TCL) and a low-resistance contact structure. In order to obtain low contact resistance between the TCL and p-GaN surface, a patterned graphene TCL with Cr/Au electrodes is suggested. A bi-layer patterning method of a graphene TCL was utilized to prevent the graphene from peeling off the p-GaN surface. To improve the work function and the sheet resistance of graphene, CVD (chemical vapor deposition) graphene was doped by a chemical treatment using a HNO(3) solution. The effect of the contact resistance on the power degradation of LEDs at a high injection current level was investigated. In addition, the enhancement of the optical power via an increase in the current spreading and a decrease in the potential barrier of the graphene TCL was investigated.
Creative Research Center for Graphene Electronics, Electronics and Telecommunications Research Institute, Daejeon, Korea. dhyoun@etri.re.kr
Doo-Hyeb
DH
Youn
Young-Jun
YJ
Yu
Hongkyw
H
Choi
Suck-Hwan
SH
Kim
Sung-Yool
SY
Choi
Choon-Gi
CG
Choi