Improved graphene growth in UHV: Pit-free surfaces by selective Si etching of SiC(0001)–Si with atomic hydrogen

Sandin, Andreas; Rowe, J. E.; Dougherty, Daniel B.

doi:10.1016/j.susc.2013.01.010

Cited by 16 publications

(18 citation statements)

References 29 publications

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“…Hydrogen can be also used to prepare atomically flat SiC surface by hydrogen etching 25 or pit-free surfaces by selective silicon etching at reduced growth temperatures. 26 The main objective of this work is to study Si-H bond formation and its temporal stability. This will provide a route towards reliable, back-gated epitaxial graphene of high carrier mobility.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen intercalation of epitaxial graphene and buffer layer probed by mid-infrared absorption and Raman spectroscopy

2018

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We have measured optical absorption in mid-infrared spectral range on hydrogen intercalated single layer epitaxial graphene and buffer layer grown on silicon face of SiC. We have used attenuated total reflection geometry to enhance absorption related to the surface and SiC/graphene interface. The Raman spectroscopy is used to show presence of buffer layer and single layer graphene prior to intercalation. We also present Raman spectra of quasi free standing monolayer and bilayer graphene after hydrogen intercalation at temperatures between 790 and 1510°C. We have found that although the Si-H bonds form at as low temperatures as 790°C, the well developed bond order has been reached only for samples intercalated at temperatures exceeding 1000°C. We also study temporal stability of hydrogen intercalated samples stored in ambient air. The optical spectroscopy shows on a formation of silyl and silylene groups on the SiC/graphene interface due to the residual atomic hydrogen left from the intercalation process.

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Section: Introductionmentioning

confidence: 99%

Hydrogen intercalation of epitaxial graphene and buffer layer probed by mid-infrared absorption and Raman spectroscopy

2018

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“…The inhomogeneity of CuPc domain sizes is attributed to the large variation in the graphene defect density, as epitaxial graphene on SiC prepared in UHV is known to be extremely spatially inhomogeneous. 23 This is reflected in our AFM measurements shown in Figure 2a and 2b that show highly variable film morphology in different macroscopic surface regions.…”

Section: Resultsmentioning

confidence: 61%

“…This surface exhibits a regular array of triple-bilayer SiC steps (height 0.75 nm) which arise from the unavoidable miscut from the perfect (0001) plane, as well as random "etch pits" because of rapid thermal desorption of Si during graphene growth. 23 The single-layer graphene grown on single crystal SiC(0001) wafers has an added advantage of forming a continuous 2-D single crystal of graphene across the sample with essentially no rotational disorder in the plane of the surface. However, the intrinsic SiC surface steps and etch pits formed during graphene growth by thermal desorption of Si in ultrahigh vacuum give our graphene on SiC(0001) substrates substantially higher defect density than cleaved graphite.…”

Section: Resultsmentioning

confidence: 99%

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Toward Single-Crystal Hybrid-Carbon Electronics: Impact of Graphene Substrate Defect Density on Copper Phthalocyanine Film Growth

McAfee

Gann

Guan

et al. 2014

Crystal Growth & Design

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Graphene has long been recognized as a potential replacement for indium tin oxide as a transparent conducting substrate that may not only be cheaper to manufacture but also may provide mechanical flexibility and templating for preferential organic film growth. Here, we report the discovery that the thin film growth mode and crystal structure of copper phthalocyanine (CuPc), a prototype organic semiconductor, is extremely sensitive to even atomic-scale defects (e.g., steps) on the graphene surface and that high quality films can be grown with a well-defined crystal orientation that should be favorable for optimized solar cell applications. The initial growth involves flat-lying copper phthalocyanine molecules in a triclinic brickstone crystal with (012̅ ) orientation. Thicker films on pristine graphite, as well as thin films on lower quality graphene, show an orientational transition to the flat-lying (112̅ )-oriented brickstone, which nucleates near film defects and grows in more compact 3D islands. The thickness dependent transition between these two flat-lying crystal orientations is sensitive to substrate defect density since this determines the extent to which initial island elongation along the substrate can alleviate strain in the film. The sensitivity of copper phthalocyanine film morphology demonstrates the extreme importance of graphene substrate quality to controlling organic film growth. The high crystallinity and optimal molecular orientation achieved here implies a new driving force for high performance organic optoelectronics based on substrate-controlled crystal engineering.

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“…Thus far, various methods have been proposed to minimize etch pit formation during graphene growth. These approaches include the use of a vicinal SiC surface, 14 deposition of evaporated C atoms onto SiC, 15,16 rapid annealing of SiC, 17 selective etching of Si atoms in surface SiC layers by atomic hydrogen, 18 and the use of high background gas pressures during heating at temperatures above 1650°C. 19 In this paper, we investigate the use of plasma to avoid a pitted morphology on SiC during subsequent heating in UHV to grow graphene.…”

Section: Introductionmentioning

confidence: 99%

Improvements in graphene growth on 4H-SiC(0001) using plasma induced surface oxidation

Minami

Ito

Hosoo

et al. 2019

Journal of Applied Physics

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A Si-face 4H-SiC surface was modified by plasma oxidation followed by HF etching. The resulting surface was covered with a carbon overlayer composed of C-C bonded clusters and Si-O-C bonding from Si 4 C 4 O 4 and Si 4 C 4−x O 2 (x < 2), as evidenced by photoemission spectroscopy measurements and wetting properties. A trend was observed in which the thickness of the carbon overlayer was proportional to the SiO 2 thickness after plasma oxidation, indicating that the former could be controlled on the subnanometer scale by adjusting plasma conditions. After a subsequent annealing under ultrahigh vacuum, we found that graphene grew on the modified SiC surface without the formation of a pitting morphology, which is in contrast to the case using an untreated SiC substrate. Raman spectroscopy revealed that the former graphene includes fewer defects than the latter graphene. We discuss the microscopic mechanism by which reaction products composed of C-C and Si-O-C bonds form in the SiO 2 film near the SiO 2 /SiC interface via plasma oxidation as well as their influence on the subsequent growth of graphene.

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Improved graphene growth in UHV: Pit-free surfaces by selective Si etching of SiC(0001)–Si with atomic hydrogen

Cited by 16 publications

References 29 publications

Hydrogen intercalation of epitaxial graphene and buffer layer probed by mid-infrared absorption and Raman spectroscopy

Hydrogen intercalation of epitaxial graphene and buffer layer probed by mid-infrared absorption and Raman spectroscopy

Toward Single-Crystal Hybrid-Carbon Electronics: Impact of Graphene Substrate Defect Density on Copper Phthalocyanine Film Growth

Improvements in graphene growth on 4H-SiC(0001) using plasma induced surface oxidation

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