Direct synthesis of multilayer graphene on an insulator by Ni-induced layer exchange growth of amorphous carbon

Murata, Hiromasa; Toko, Kaoru; Saitoh, Noriyuki; Yoshizawa, Noriko; Suemasu, Takashi

doi:10.1063/1.4974318

Cited by 28 publications

(56 citation statements)

References 38 publications

(63 reference statements)

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“…A layer exchange mechanism of this kind was also observed for amorphous carbon/Ni heterostructures. 23 − 25 Then the graphitic layers are formed at T > 500 °C ( Figure 7 c) according to results observed from XPS measurements. Finally, the graphitic phase concentration increases with the annealing temperature ( T > 700 °C), and its concentration became higher than the concentration of the disordered phase ( Figure 7 d).…”

Section: Resultssupporting

confidence: 64%

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Study of Ni-Catalyzed Graphitization Process of Diamond by in Situ X-ray Photoelectron Spectroscopy

et al. 2018

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Graphene on diamond has been attracting considerable attention due to the unique and highly beneficial features of this heterostructure for a range of electronic applications. Here, ultrahigh-vacuum X-ray photoelectron spectroscopy is used for in situ analysis of the temperature dependence of the Ni-assisted thermally induced graphitization process of intrinsic nanocrystalline diamond thin films (65 nm thickness, 50–80 nm grain size) on silicon wafer substrates. Three major stages of diamond film transformation are determined from XPS during the thermal annealing in the temperature range from 300 °C to 800 °C. Heating from 300 °C causes removal of oxygen; formation of the disordered carbon phase is observed at 400 °C; the disordered carbon progressively transforms to graphitic phase whereas the diamond phase disappears from the surface from 500 °C. In the well-controllable temperature regime between 600 °C and 700 °C, the nanocrystalline diamond thin film is mainly preserved, while graphitic layers form on the surface as the predominant carbon phase. Moreover, the graphitization is facilitated by a disordered carbon interlayer that inherently forms between diamond and graphitic layers by Ni catalyst. Thus, the process results in formation of a multilayer heterostructure on silicon substrate.

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Section: Resultssupporting

confidence: 64%

“…It was observed that carbon film exchanges with Ni film and graphitizes at elevated temperature. 23 − 25 Recent theoretical studies explained the graphitization mechanism for RTA: a-C to graphene transformation entails the metal-induced crystallization and layer exchange mechanism. Carbon dissolution in Ni was excluded.…”

Section: Introductionmentioning

confidence: 99%

Study of Ni-Catalyzed Graphitization Process of Diamond by in Situ X-ray Photoelectron Spectroscopy

et al. 2018

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“…We prepared the samples with and without a diffusion controlling Al 2 O 3 IL, which improves the crystal quality of MLG 42 . The thickness of the initial Ni layer determines the resulting MLG thickness, t , after layer exchange 41 , 42 . We varied t from 5 nm to 200 nm to investigate the effects of t on the crystal and electrical properties of the MLG.…”

Section: Resultsmentioning

confidence: 99%

“…The thickness design of the initial metal layer can easily control the resulting semiconductor layer 27 , 31 , 35 . We found the layer exchange occurs in the Co-C and Ni-C systems and fabricated a uniform 50-nm-thick MLG on an insulator 40 , 41 . Furthermore, we employed a diffusion controlling interlayer (IL) between C and Ni, which suppresses the nucleation of the MLG and results in enlargement of MLG grains 42 .…”

Section: Introductionmentioning

confidence: 91%

High-Electrical-Conductivity Multilayer Graphene Formed by Layer Exchange with Controlled Thickness and Interlayer

Murata

Nakajima

Saitoh

et al. 2019

Sci Rep

109

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The layer exchange technique enables high-quality multilayer graphene (MLG) on arbitrary substrates, which is a key to combining advanced electronic devices with carbon materials. We synthesize uniform MLG layers of various thicknesses, t, ranging from 5 nm to 200 nm using Ni-induced layer exchange at 800 °C. Raman and transmission electron microscopy studies show the crystal quality of MLG is relatively low for t ≤ 20 nm and dramatically improves for t ≥ 50 nm when we prepare a diffusion controlling Al2O3 interlayer between the C and Ni layers. Hall effect measurements reveal the carrier mobility for t = 50 nm is 550 cm2/Vs, which is the highest Hall mobility in MLG directly formed on an insulator. The electrical conductivity (2700 S/cm) also exceeds a highly oriented pyrolytic graphite synthesized at 3000 °C or higher. Synthesis technology of MLG with a wide range of thicknesses will enable exploration of extensive device applications of carbon materials.

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“…Recently, we developed metal-induced layer exchange (MILE) of a-C. 28−32 In particular, MILE using Ni enabled us to synthesize uniform MLG at low temperature with a wide range of thicknesses. 29,32 Higashi et al reported the effects of an a-Ge/Au multilayer structure on the layer exchange between Au and Ge. 33,34 The grain size of the resulting Ge layer was significantly improved by using the multilayer structure.…”

Section: Introductionmentioning

confidence: 99%

Impact of Amorphous-C/Ni Multilayers on Ni-Induced Layer Exchange for Multilayer Graphene on Insulators

et al. 2019

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Layer exchange growth of amorphous carbon (a-C) is a unique technique for fabricating high-quality multilayer graphene (MLG) on insulators at low temperatures. We investigated the effects of the a-C/Ni multilayer structure on the quality of MLG formed by Ni-induced layer exchange. The crystal quality and electrical conductivity of MLG improved dramatically as the number of a-C/Ni multilayers increased. A 600 °C-annealed sample in which 15 layers of 4-nm-thick a-C and 0.5-nm-thick Ni were laminated recorded an electrical conductivity of 1430 S/cm. This value is close to that of highly oriented pyrolytic graphite synthesized at approximately 3000 °C. This improvement is likely related to the bond weakening in a-C due to the screening effect of Ni. We expect that these results will contribute to low-temperature synthesis of MLG using a solid-phase reaction with metals.

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Direct synthesis of multilayer graphene on an insulator by Ni-induced layer exchange growth of amorphous carbon

Cited by 28 publications

References 38 publications

Study of Ni-Catalyzed Graphitization Process of Diamond by in Situ X-ray Photoelectron Spectroscopy

Study of Ni-Catalyzed Graphitization Process of Diamond by in Situ X-ray Photoelectron Spectroscopy

High-Electrical-Conductivity Multilayer Graphene Formed by Layer Exchange with Controlled Thickness and Interlayer

Impact of Amorphous-C/Ni Multilayers on Ni-Induced Layer Exchange for Multilayer Graphene on Insulators

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