Transfer-free fabrication of a graphene transparent electrode on a GaN-based light-emitting diode using the direct precipitation method

Yamada, Jumpei; Usami, Shigeyoshi; Ueda, Yuki; Honda, Yoshio; Amano, Hiroshi; Maruyama, Toru; Naritsuka, Shigeya

doi:10.7567/1347-4065/aafe70

Cited by 11 publications

(8 citation statements)

References 31 publications

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“…This peak is termed as the "shake-up satellite peak" in literature. It usually corresponds to the π-π* transition occurring in a sp 2 -carbon sixmembered ring [58]. Table 2 summarizes the BE of the peaks observed (after carbon correction) and the corresponding BE reported in literature.…”

Section: Xpsmentioning

confidence: 98%

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AlGaN nanowire deep ultraviolet light emitting diodes with graphene electrode

Parimoo

Zhang

Vafadar

et al. 2022

Applied Physics Letters

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Despite graphene being an attractive transparent conductive electrode for semiconductor deep ultraviolet (UV) light emitting diodes (LEDs), there have been no experimental demonstrations of any kind of semiconductor deep UV LEDs using a graphene electrode. Moreover, although aluminum gallium nitride (AlGaN) alloys in the format of nanowires are an appealing platform for surface-emitting vertical semiconductor deep UV LEDs, in particular, at short wavelengths, there are few demonstrations of AlGaN nanowire UV LEDs with a graphene electrode. In this work, we show that transferred graphene can serve as the top electrode for AlGaN nanowire deep UV LEDs, and devices emitting down to around 240 nm are demonstrated. Compared to using metal, graphene improves both the light output power and external quantum efficiency. Nonetheless, devices with a graphene electrode show a more severe efficiency droop compared to devices with metal. Here, we attribute the heating effect associated with the large contact resistance to be the major reason for the severe efficiency droop in the devices with a graphene electrode. Detailed scanning electron microscopy and Raman scattering experiments suggest that the nanowire height nonuniformity is the main cause for the large contact resistance; this issue could be potentially alleviated by using nanowires grown by selective area epitaxy that is able to produce nanowires with uniform height. This work, therefore, not only demonstrates the shortest wavelength LEDs using a graphene electrode but also provides a viable path for surface-emitting vertical semiconductor deep UV LEDs at short wavelengths.

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Section: Xpsmentioning

confidence: 98%

“…spectra scan of binding energy (BE) obtained for three regions on the device, at a pass energy of 200 eV. All regions of the device show the expected characteristic peaks of Ga 3d, Al 2p, N 1s, O 1s and C 1s [58], [92], [93].…”

Section: Xpsmentioning

confidence: 99%

AlGaN nanowire deep ultraviolet light emitting diodes with graphene electrode

Parimoo

Zhang

Vafadar

et al. 2022

Applied Physics Letters

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“…Graphene directly grown on the p-side of GaN-based LEDs is expected to solve problems originating from the transfer process, such as bad adhesion, polymer residuals, defects and other damage introduced during transfer. Three main methods for direct integration of graphene layers as TCSL into GaN-based LED are reported: spray deposition of a graphene dispersion solution with a subsequent heating treatment (chemically converted graphene, CCG) [ 50 , 63 ], catalyzed graphene growth with W/Ni using rapid thermal annealing (RTA) post processing [ 64 ] and plasma enhanced chemical vapor deposition (PECVD) with [ 65 , 66 ] and without catalysts [ 67 , 68 ].…”

Section: Graphene As Tcsl In Gan-based Ledsmentioning

confidence: 99%

“…Similarly, graphene grown with a W/Ni catalyst shows an optical transmission above 84% in the UV-VIS range. However, its high sheet resistance of 6 kΩ/sq and the extraordinary high

of 10 V at 0.4 mA need to be improved [ 64 ]. Only PECVD-grown graphene TCSLs with Co-catalyst [ 66 ] or without catalyst (see Figure 2 a) show a

below 5 V at 20 mA input current.…”

Section: Graphene As Tcsl In Gan-based Ledsmentioning

confidence: 99%

Graphene as a Transparent Conductive Electrode in GaN-Based LEDs

et al. 2022

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Graphene combines high conductivity (sheet resistance down to a few hundred Ω/sq and even less) with high transparency (>90%) and thus exhibits a huge application potential as a transparent conductive electrode in gallium nitride (GaN)-based light-emitting diodes (LEDs), being an economical alternative to common indium-based solutions. Here, we present an overview of the state-of-the-art graphene-based transparent conductive electrodes in GaN-based LEDs. The focus is placed on the manufacturing progress and the resulting properties of the fabricated devices. Transferred as well as directly grown graphene layers are considered. We discuss the impact of graphene-based transparent conductive electrodes on current spreading and contact resistance, and reveal future challenges and perspectives on the use of graphene in GaN-based LEDs.

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“…[13][14][15][16][17][18][19] Our group has developed a method for the direct precipitation of graphene using a capping layer, which has the advantage of controlling the direction of precipitation from the top to the bottom of a catalyst. [20][21][22] Using this technique, graphene has been grown directly not only on sapphire substrates but also on a wafer of blue light emitting diode. In the latter case, the graphene was used to produce a transparent electrode for current injection.…”

mentioning

confidence: 99%

Nanodiamond as the carbon source for precipitation of multilayer graphene on a Si substrate

Kashio

Nakashima

Murahashi

et al. 2022

Jpn. J. Appl. Phys.

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Nanodiamond was used to directly precipitate graphene at the interface between Ni catalyst and Si substrate. Consequently, multilayer graphene was successfully precipitated without using a capping layer. The critical temperature for the precipitation was found as low as 370oC, which was more than 100 degrees lower than that of the conventional amorphous carbon case. The annealing temperature of 900oC offers high-quality graphene with low D/G ratio of 0.06. The nanodiamond contributes to increase the carbon concentration in the catalyst, which brought both graphene nucleation at the interface and very low critical temperature.

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Transfer-free fabrication of a graphene transparent electrode on a GaN-based light-emitting diode using the direct precipitation method

Cited by 11 publications

References 31 publications

AlGaN nanowire deep ultraviolet light emitting diodes with graphene electrode

AlGaN nanowire deep ultraviolet light emitting diodes with graphene electrode

Graphene as a Transparent Conductive Electrode in GaN-Based LEDs

Nanodiamond as the carbon source for precipitation of multilayer graphene on a Si substrate

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