Opposite Behavior of Multilayer Graphene/ Indium-Tin-Oxide -Electrode for Gallium Nitride Based-Light Emitting Diodes Depending on Thickness of Indium-Tin-Oxide Layer.

Title Opposite Behavior of Multilayer Graphene/ Indium-Tin-Oxide -Electrode for Gallium Nitride Based-Light Emitting Diodes Depending on Thickness of Indium-Tin-Oxide Layer.
Authors T.Kyoung Kim; Y.Jin Yoon; S.Kyu Oh; Y.J. Cha; I.Yeol Hong; M.Uk Cho; C.H. Hong; H.Kyw Choi; J.Seop Kwak
Journal J Nanosci Nanotechnol
DOI 10.1166/jnn.2018.15603
Abstract

In order to improve EQE, we have investigated on the role of multilayer graphene (MLG) on the electrical and optical properties of GaN based light-emitting diodes (LEDs) with ultrathin ITO (5 nm or 10 nm)/p-GaN contacts. The MLG was transferred on the ITO/p-GaN to decrease sheet resistance of thin ITO p-electrode and improve the current spreading of LEDs. The LEDs with the ITO 5 nm and MLG/ITO 5 nm structures showed 3.25 and 3.06 V at 20 mA, and 11.69 and 13.02 mW/sr at 400 mA, respectively. After forming MLG on ITO 5 nm, the electro-optical properties were enhanced. Furthermore, the GaN based-LEDs applied to the ITO 10 nm, and MLG/ITO (10 nm) structures showed 2.95 and 3.06 V at 20 mA, and 20.28 and 16.74 mW/sr at 400 mA, respectively. The sheet resistance of the MLG transferred to ITO 5 nm was decreased approximately four fold compared to ITO 5 nm. On the other hand, the ITO 10 nm and MLG/ITO 10 nm showed a similar sheet resistance; the transmittance of the LEDs with ITO 10 nm decreased to 16% due to MLG formation on ITO. This suggests that the relationship between the sheet resistance and transmittance according to the ITO film thickness affected the electro-optical properties of the LEDs with a transparent p-electrode with the MLG/ITO dual structure.

Citation T.Kyoung Kim; Y.Jin Yoon; S.Kyu Oh; Y.J. Cha; I.Yeol Hong; M.Uk Cho; C.H. Hong; H.Kyw Choi; J.Seop Kwak.Opposite Behavior of Multilayer Graphene/ Indium-Tin-Oxide -Electrode for Gallium Nitride Based-Light Emitting Diodes Depending on Thickness of Indium-Tin-Oxide Layer.. J Nanosci Nanotechnol. 2018;18(9):61066111. doi:10.1166/jnn.2018.15603

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