We produced epitaxial graphene under a moderate pressure of 4 mbar （about 400 Pa） at temperature 1600 ℃. Raman spectroscopy and optical microscopy were used to confirm that epitaxial graphene has taken shape contin...We produced epitaxial graphene under a moderate pressure of 4 mbar （about 400 Pa） at temperature 1600 ℃. Raman spectroscopy and optical microscopy were used to confirm that epitaxial graphene has taken shape continually with slight thickness variations and regularly with a centimeter order of magnitude on 4H-SiC （0001） substrates. Then using X-ray photoelectron spectroscopy and Auger electron spectroscopy, we analyzed the chemical compositions and estimated the layer number of epitaxial graphene. Finally, an atomic force microscope and a scanning force microscope were used to characterize the morphological structure. Our results showed that under 4-mbar pressure, epitaxial graphene could be produced on a SiC substrate with a large area, uniform thickness but a limited morphological property. We hope our work will be of benefit to understanding the formation process of epitaxial graphene on SiC substrate in detail.展开更多
In this paper, we report a feasible route of growing epitaxial graphene on 4H-SiC （0001） substrate in a low pressure of 4 mbar （1 bar=105 Pa） with an argon flux of 2 standard liters per minute at 1200, 1300, 1400,...In this paper, we report a feasible route of growing epitaxial graphene on 4H-SiC （0001） substrate in a low pressure of 4 mbar （1 bar=105 Pa） with an argon flux of 2 standard liters per minute at 1200, 1300, 1400, and 1500 ℃ in a commercial chemical vapour deposition SiC reactor. Using Raman spectroscopy and scanning electron microscopy, we confirm that epitaxial graphene evidently forms on SiC surface above 1300 ℃ with a size of several microns. By fitting the 2D band of Raman data with two-Lorentzian function, and comparing with the published reports, we conclude that epitaxial graphene grown at 1300 ℃ is four-layer graphene.展开更多
In this paper,the epitaxial graphene layers grown on Si-and C-face 6H-SiC substrates are investigated under a low pressure of 400 Pa at 1600 C.By using atomic force microscopy and Raman spectroscopy,we find that there...In this paper,the epitaxial graphene layers grown on Si-and C-face 6H-SiC substrates are investigated under a low pressure of 400 Pa at 1600 C.By using atomic force microscopy and Raman spectroscopy,we find that there are distinct differences in the formation and the properties between the epitaxial graphene layers grown on the Si-face and the C-face substrates,including the hydrogen etching process,the stacking type,and the number of layers.Hopefully,our results will be useful for improving the quality of the epitaxial graphene on SiC substrate.展开更多
基金supported by the Key Specific Projects in the National Science&Technology Program,China(Grant No.2011ZX02707)the Key Research Foundationfrom the Ministry of Education of China(Grant No.JY10000925016)the Specialized Research Fund from Xianyang Normal University,China(GrantNos.13XSYK010 and 201302026)
文摘We produced epitaxial graphene under a moderate pressure of 4 mbar （about 400 Pa） at temperature 1600 ℃. Raman spectroscopy and optical microscopy were used to confirm that epitaxial graphene has taken shape continually with slight thickness variations and regularly with a centimeter order of magnitude on 4H-SiC （0001） substrates. Then using X-ray photoelectron spectroscopy and Auger electron spectroscopy, we analyzed the chemical compositions and estimated the layer number of epitaxial graphene. Finally, an atomic force microscope and a scanning force microscope were used to characterize the morphological structure. Our results showed that under 4-mbar pressure, epitaxial graphene could be produced on a SiC substrate with a large area, uniform thickness but a limited morphological property. We hope our work will be of benefit to understanding the formation process of epitaxial graphene on SiC substrate in detail.
基金Project supported by the Key Research Foundation of the Ministry of Education of China (Grant No. JY10000925016)
文摘In this paper, we report a feasible route of growing epitaxial graphene on 4H-SiC （0001） substrate in a low pressure of 4 mbar （1 bar=105 Pa） with an argon flux of 2 standard liters per minute at 1200, 1300, 1400, and 1500 ℃ in a commercial chemical vapour deposition SiC reactor. Using Raman spectroscopy and scanning electron microscopy, we confirm that epitaxial graphene evidently forms on SiC surface above 1300 ℃ with a size of several microns. By fitting the 2D band of Raman data with two-Lorentzian function, and comparing with the published reports, we conclude that epitaxial graphene grown at 1300 ℃ is four-layer graphene.
基金Project supported by the Key Research Foundation from the Ministry of Education of China (Grant No. JY10000925016)
文摘In this paper,the epitaxial graphene layers grown on Si-and C-face 6H-SiC substrates are investigated under a low pressure of 400 Pa at 1600 C.By using atomic force microscopy and Raman spectroscopy,we find that there are distinct differences in the formation and the properties between the epitaxial graphene layers grown on the Si-face and the C-face substrates,including the hydrogen etching process,the stacking type,and the number of layers.Hopefully,our results will be useful for improving the quality of the epitaxial graphene on SiC substrate.
