Journal Home > Volume 8 , Issue 3

The hydrogenation at various temperatures of the (6√3 × 6√3)R30° reconstruction of SiC(0001), the so-called buffer layer graphene (BLG), is investigated. For the BLG, a significant concentration of remaining dangling bonds related to unsaturated Si atoms of the outermost SiC bilayer is evidenced in the inverse photoemission spectra. These dangling bonds give rise to a peak around 1 eV above the Fermi level, associated with the upper single-electron states of a Mott-Hubbard insulator, which vanishes upon hydrogenation. Hydrogen atoms adsorbed at ambient temperature remain covalently bound to BLG (H-BLG) up to temperatures of ~500 ℃. They induce additional C-Si bonds at the BLG/SiC interface that saturate the remaining Si dangling bonds, as evidenced in both IPES and Auger electron spectra. The H-BLG further shows a large energy gap and an excess n-type doping in comparison to the pristine BLG. Upon hydrogen exposure at higher temperature (> 700 ℃), hydrogen atoms intercalate at the BLG/SiC interface, inducing the formation of a single layer of quasi-free-standing graphene (QFSG) lying on top of a hydrogenated (√3 × √3)R30° reconstruction as supported by IPES. We suggest that the high-stability and the distinct electronic structure of both BLG-derived structures, H-BLG and QFSG, may open a route for the engineering of graphene-based devices.


menu
Abstract
Full text
Outline
About this article

Hydrogenation of the buffer-layer graphene on 6H-SiC (0001): A possible route for the engineering of graphene-based devices

Show Author's information Yu-Pu Lin( )Younal KsariJean-Marc Themlin( )
Aix-Marseille Université, CNRSUniversité de ToulonIM2NP, UMR 733413397Marseille, France

Abstract

The hydrogenation at various temperatures of the (6√3 × 6√3)R30° reconstruction of SiC(0001), the so-called buffer layer graphene (BLG), is investigated. For the BLG, a significant concentration of remaining dangling bonds related to unsaturated Si atoms of the outermost SiC bilayer is evidenced in the inverse photoemission spectra. These dangling bonds give rise to a peak around 1 eV above the Fermi level, associated with the upper single-electron states of a Mott-Hubbard insulator, which vanishes upon hydrogenation. Hydrogen atoms adsorbed at ambient temperature remain covalently bound to BLG (H-BLG) up to temperatures of ~500 ℃. They induce additional C-Si bonds at the BLG/SiC interface that saturate the remaining Si dangling bonds, as evidenced in both IPES and Auger electron spectra. The H-BLG further shows a large energy gap and an excess n-type doping in comparison to the pristine BLG. Upon hydrogen exposure at higher temperature (> 700 ℃), hydrogen atoms intercalate at the BLG/SiC interface, inducing the formation of a single layer of quasi-free-standing graphene (QFSG) lying on top of a hydrogenated (√3 × √3)R30° reconstruction as supported by IPES. We suggest that the high-stability and the distinct electronic structure of both BLG-derived structures, H-BLG and QFSG, may open a route for the engineering of graphene-based devices.

Keywords: graphene, electronic structure, photoemission spectroscopy, hydrogenation

References(55)

1

Novoselov, K. S.; Geim, A. K.; Morozov, S. V.; Jiang, D.; Zhang, Y.; Dubonos, S. V.; Grigorieva, I. V.; Firsov, A. A. Electric field effect in atomically thin carbon films. Science 2004, 306, 666-669.

2

Stoller, M. D.; Park, S.; Zhu, Y. W.; An, J.; Ruoff, R. S. Graphene-based ultracapacitors. Nano Lett. 2008, 8, 3498-3502.

3

Lee, C.; Wei, X.; Kysar, J. W.; Hone, J. Measurement of the elastic properties and intrinsic strength of monolayer graphene. Science 2008, 321, 385-388.

4

Balandin, A. A.; Ghosh, S.; Bao, W. Z.; Calizo, I.; Teweldebrhan, D.; Miao, F.; Lau, C. N. Superior thermal conductivity of single-layer graphene. Nano Lett. 2008, 8, 902-907.

5

Wu, J. B.; Becerril, H. A.; Bao, Z. N.; Liu, Z. F.; Chen, Y. S.; Peumans, P. Organic solar cells with solution-processed graphene transparent electrodes. Appl. Phys. Lett. 2008, 92, 263302.

6

Schedin, F.; Geim, A. K.; Morozov, S. V.; Hill, E.; Blake, P.; Katsnelson, M. I.; Novoselov, K. S. Detection of individual gas molecules adsorbed on graphene. Nat. Mater. 2007, 6, 652-655.

7

Darkrim Lamari, F.; Levesque, D. Hydrogen adsorption on functionalized graphene. Carbon 2011, 49, 5196-5200.

8

Berger, C.; Song, Z. M.; Li, T. B.; Li, X. B.; Ogbazghi, A. Y.; Feng, R.; Dai, Z. T.; Marchenkov, A. N.; Conrad, E. H.; First, P. N.; de Heer, W. A. Ultrathin epitaxial graphite: 2D electron gas properties and a route toward graphene-based nanoelectronics. J. Phys. Chem. B 2004, 108, 19912-19916.

9

Riedl, C.; Coletti, C.; Starke, U. Structural and electronic properties of epitaxial graphene on SiC(0001): A review of growth, characterization, transfer doping and hydrogen intercalation. J. Phys. D: Appl. Phys. 2010, 43, 374009.

10

Forbeaux, I.; Themlin, J. M.; Debever, J. M. Heteroepitaxial graphite on 6H-SiC(0001): Interface formation through conduction-band electronic structure. Phys. Rev. B 1998, 58, 16396-16406.

11

Riedl, C.; Coletti, C.; Iwasaki, T.; Zakharov, A. A.; Starke, U. Quasifree-standing epitaxial graphene on SiC obtained by hydrogen intercalation. Phys. Rev. Lett. 2009, 103, 246804.

12

Sclauzero, G.; Pasquarello, A. Carbon rehybridization at the graphene/SiC(0001) interface: Effect on stability and atomic-scale corrugation. Phys. Rev. B 2012, 85, 161405.

13

Bocquet, F. C.; Bisson, R.; Themlin, J. M.; Layet, J. M.; Angot, T. Reversible hydrogenation of deuterium-intercalated quasi-free-standing graphene on SiC(0001). Phys. Rev. B 2012, 85, 201401.

14

Elias, D. C.; Nair, R. R.; Mohiuddin, T. M. G.; Morozov, S. V.; Blake, P.; Halsall, M. P.; Ferrari, A. C.; Boukhvalov, D. W.; Katsnelson, M. I.; Geim, A. K. et al. Control of graphene's properties by reversible hydrogenation: Evidence for graphane. Science 2009, 323, 610-613.

15

Haberer, D.; Vyalikh, D. V.; Taioli, S.; Dora, B.; Farjam, M.; Fink, J.; Marchenko, D.; Pichler, T.; Ziegler, K.; Simonucci, S. et al. Tunable band gap in hydrogenated quasi-free-standing graphene. Nano Lett. 2010, 10, 3360-3366.

16

Bocquet, F. C.; Bisson, R.; Themlin, J. M.; Layet, J. M.; Angot, T. Deuterium adsorption on (and desorption from) SiC(0001)-(3 × 3), (√3 × √3)R30°, (6√3 × 6√3)R30° and quasi-free-standing graphene obtained by hydrogen intercalation. J. Phys. D: Appl. Phys. 2014, 47, 094014.

17

Ao, Z. M.; Hernández-Nieves, A. D.; Peeters, F. M.; Li, S. Enhanced stability of hydrogen atoms at the graphene/graphane interface of nanoribbons. Appl. Phys. Lett. 2010, 97, 233109.

18

Guisinger, N. P.; Rutter, G. M.; Crain, J. N.; First, J. N.; Stroscio, J. A. Exposure of epitaxial graphene on SiC(0001) to atomic hydrogen. Nano Lett. 2009, 9, 1462-1466.

19

Lee, B.; Han, S.; Kim, Y. S. First-principles study of preferential sites of hydrogen incorporated in epitaxial graphene on 6H-SiC(0001). Phys. Rev. B 2010, 81, 075432.

20

Sclauzero, G.; Pasquarello, A. First-principles study of H adsorption on graphene/SiC(0001). Phys. Status Solidi B 2013, 250, 2523-2528.

21

Sofo, J. O.; Chaudhari, A. S.; Barber, G. D. Graphane: A two-dimensional hydrocarbon. Phys. Rev. B 2007, 75, 153401.

22

Savini, G.; Ferrari, A. C.; Giustino, F. First-principles prediction of doped graphane as a high-temperature electron-phonon superconductor. Phys. Rev. Lett. 2010, 105, 037002.

23

Lebègue, S.; Klintenberg, M.; Eriksson, O.; Katsnelson, M. I. Accurate electronic band gap of pure and functionalized graphane from GW calculations. Phys. Rev. B 2009, 79, 245117.

24

Lin, Y. P.; Ksari, Y.; Prakash, J.; Giovanelli, L.; Valmalette, J. C.; Themlin, J. M. Nitrogen-doping processes of graphene by a versatile plasma-based method. Carbon 2014, 73, 216-224.

25

Langlais, V.; Belkhir, H.; Themlin, J. M.; Debever, J. M.; Yu, L. M.; Thiry, P. A. Initial- and final-state effects in the conduction bands of 2H-MoS2(0001) studied by k||-resolved inverse photoemission spectroscopy. Phys. Rev. B 1995, 52, 12095-12101.

26

Komolov, S. A.; Chadderton, L. T. Total current spectroscopy. Surf. Sci. 1979, 90, 359-380.

27

Haas, T. W.; Grant, J. T.; Dooley, G. J. Ⅲ. Chemical effects in Auger electron spectroscopy. J. Appl. Phys. 1972, 43, 1853-1860.

28

Van Bommel, A. J.; Crombeen, J. E.; Van Tooren, A. LEED and Auger electron observations of the SiC(0001) surface. Surf. Sci. 1975, 48, 463-472.

29

Mattausch, A.; Pankratov, O. Ab initio study of graphene on SiC. Phys. Rev. Lett. 2007, 99, 076802.

30

Emtsev, K. V.; Speck, F.; Seyller, T.; Ley, L.; Riley, J. D. Interaction, growth, and ordering of epitaxial graphene on SiC(0001) surfaces: A comparative photoelectron spectroscopy study. Phys. Rev. B 2008, 77, 155303.

31

Varchon, F.; Feng, R.; Hass, J.; Li, X.; Nguyen, B. N.; Naud, C.; Mallet, P.; Veuillen, J. Y.; Berger, C.; Conrad, E. H.; Magaud, L. Electronic structure of epitaxial graphene layers on SiC: Effect of the substrate. Phys. Rev. Lett. 2007, 99, 126805.

32

Deretzis, I.; La Magna, A. Interaction between hydrogen flux and carbon monolayer on SiC(0001): Graphene formation kinetics. Nanoscale 2013, 5, 671.

33

Lee, B.; Han, S.; Kim, Y. S. First-principles study of preferential sites of hydrogen incorporated in epitaxial graphene on 6H-SiC(0001). Phys. Rev. B 2010, 81, 075432.

34

Sclauzero, G.; Pasquarello, A. Intercalation of H at the graphene/SiC(0001) interface: Structure and stability from first principles. Appl. Surf. Sci. 2014, 291, 64-68.

35

Kim, S.; Ihm, J.; Choi, H. J.; Son, Y. W. Origin of anomalous electronic structures of epitaxial graphene on silicon carbide. Phys. Rev. Lett. 2008, 100, 176802.

36

Lauffer, P.; Emtsev, K. V.; Graupner, R.; Seyller, T.; Ley, L.; Reshanov, S. A.; Weber, H. B. Atomic and electronic structure of few-layer graphene on SiC(0001) studied with scanning tunneling microscopy and spectroscopy. Phys. Rev. B 2008, 77, 155426.

37

Hass, J.; Millán-Otoya, J. E.; First, P. N.; Conrad, E. H. Interface structure of epitaxial graphene grown on 4H-SiC(0001). Phys. Rev. B 2008, 78, 205424.

38

Veuillen, J. Y.; Hiebel, F.; Magaud, L.; Mallet, P.; Varchon, F. Interface structure of graphene on SiC: An ab initio and STM approach. J. Phys. D: Appl. Phys. 2010, 43, 374008.

39

Sclauzero, G.; Pasquarello, A. Stability and charge transfer at the interface between SiC(0001) and epitaxial graphene. Microelectron. Eng. 2011, 88, 1478-1481.

40

de Lima, L. H.; de Siervo, A.; Landers, R.; Viana, G. A.; Goncalves, A. M. B.; Lacerda, R. G.; Häberle, P. Atomic surface structure of graphene and its buffer layer on SiC(0001): A chemical-specific photoelectron diffraction approach. Phys. Rev. B 2013, 87, 081403.

41

Emery, J. D.; Detlefs, B.; Karmel, H. J.; Nyakiti, L. O.; Gaskill, D. K.; Hersam, M. C.; Zegenhagen, J.; Bedzyk, M. J. Chemically resolved interface structure of epitaxial graphene on SiC(0001). Phys. Rev. Lett. 2013, 111, 215501.

42
Two C1s components related to BLG, S1 and S2 located at ~285 and ~285.7 eV, are found in both studies. In Ref. [30], S1 is assigned to C atoms in sp3 configuration, and its peak area is much smaller than S2. In Ref. [41], it is the component S2 that is assigned to C atoms in sp3. The peak areas of S1 and S2 are also reversed (smaller S2).
43

Norimatsu, W.; Kusunoki, M. Transitional structures of the interface between graphene and 6H-SiC(0001). Chem. Phys. Lett. 2009, 468, 52-56.

44

Themlin, J. M.; Forbeaux, I.; Langlais, V.; Belkhir, H.; Debever, J. M. Unoccupied surface state on the (√3 × √3)R30° of 6H-SiC(0001). Europhys. Lett. 1997, 39, 61.

45

Johansson, L. S. O.; Duda, L.; Laurenzis, M.; Krieftewirth, M.; Reihl, B. Electronic structure of the 6H-SiC(0001)-3 × 3 surface studied with angle resolved inverse and direct photoemission. Surf. Sci. 2000, 445, 109-114.

46

Ostendorf, R.; Wulff, K.; Benesch, C.; Merz, H.; Zacharias, H. Unoccupied Mott-Hubbard state on the (√3 × √3)R30° reconstructed 4H-SiC(0001) surface. Phys. Rev. B 2004, 70, 205325.

47

Benesch, C.; Fartmann, M.; Merz, H. k-resolved inverse photoemission of four different 6H-SiC(0001) surfaces. Phys. Rev. B 2001, 64, 205314.

48

Bocquet, F. C.; Ksari, Y.; Giovanelli, L.; Porte, L.; Themlin, J. M. High temperature desorption of C60 covalently bound to 6H-SiC(0001)-(3 × 3). Phys. Rev. B 2011, 84, 075333.

49

Charrier, A.; Pérez, R.; Thibaudau, F.; Debever, J. M.; Ortega, J.; Flores, F.; Themlin, J. M. Contrasted electronic properties of Sn-adatom based (√3 × √3)R30° reconstructions on Si(111). Phys. Rev. B 2001, 64, 115407.

50

Furthmüller, J.; Bechstedt, F.; Hüsken, B.; Schröter, B.; Richter, W. Si-rich SiC(111)/(0001) (3 × 3) and (√3 × √3) surfaces: A Mott-Hubbard picture. Phys. Rev. B 1998, 58, 13712-13716.

51

Yang, M.; Nurbawono, A.; Zhang, C.; Wu, R. Q.; Feng, Y. P.; Ariando. Manipulating absorption and diffusion of H atom on graphene by mechanical strain. AIP Adv. 2011, 1, 032109.

52

Ristein, J.; Mammadov, S.; Seyller, T. Origin of doping in quasi-freestanding graphene on silicon carbide. Phys. Rev. Lett. 2012, 108, 246104.

53
The positions of the occupied states are estimated based on the experimental values obtained on BLG reported in Refs. [18] and [30].
54

Choi, Y. S.; Wu, X.; Lee, D. W. Selective nano-patterning of graphene using a heated atomic force microscope tip. Rev. Sci. Instrum. 2014, 85, 045002.

55

Bocquet, F. C.; Ksari, Y.; Lin, Y. P.; Porte, L.; Themlin, J. M. Interaction of C60 with clean and hydrogenated SiC-(3 × 3) probed through the unoccupied electronic states. Phys. Rev. B 2013, 88, 125421.

Publication history
Copyright
Acknowledgements

Publication history

Received: 06 June 2014
Revised: 07 August 2014
Accepted: 18 August 2014
Published: 25 September 2014
Issue date: March 2015

Copyright

© Tsinghua University Press and Springer-Verlag Heidelberg 2014

Acknowledgements

Acknowledgements

This work is supported by the project ANR-10-BLAN 1017 ChimiGraphN.

Return