1. |
- Niemi, MEK, et al.
(författare)
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- 2021
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swepub:Mat__t
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2. |
- Kanai, M, et al.
(författare)
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- 2023
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swepub:Mat__t
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3. |
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4. |
- Vaziri, Sam, et al.
(författare)
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Going ballistic : Graphene hot electron transistors
- 2015
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Ingår i: Solid State Communications. - : Elsevier. - 0038-1098 .- 1879-2766. ; 224, s. 64-75
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Tidskriftsartikel (refereegranskat)abstract
- This paper reviews the experimental and theoretical state of the art in ballistic hot electron transistors that utilize two-dimensional base contacts made from graphene, i.e. graphene base transistors (GBTs). Early performance predictions that indicated potential for THz operation still hold true today, even with improved models that take non-idealities into account. Experimental results clearly demonstrate the basic functionality, with on/off current switching over several orders of magnitude, but further developments are required to exploit the full potential of the GBT device family. In particular, interfaces between graphene and semiconductors or dielectrics are far from perfect and thus limit experimental device integrity, reliability and performance.
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5. |
- Lippert, G., et al.
(författare)
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Molecular beam epitaxy of graphene on mica
- 2012
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Ingår i: Physica status solidi. B, Basic research. - : Wiley. - 0370-1972 .- 1521-3951. ; 249:12, s. 2507-2510
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Tidskriftsartikel (refereegranskat)abstract
- Realization of graphene devices is often hindered by the fact that the known layer growth methods do not meet the requirements of the device fabrication in silicon mainstream technology. For example, the relatively straightforward method of decomposition of hexagonal SiC is not CMOS-compatible due to the high-thermal budget it requires [Moon et al., IEEE Electron Device Lett. 31, 260 (2010)]. Techniques based on layer transfer are restricted because of the uncertainty of residual metal contaminants, particles, and structural defects. Of interest is thus a method that would allow one to grow a graphene film directly in the device area where graphene is needed. Production of large area graphene is not necessarily required in this case, but high quality of the film and metal-free growth on an insulating substrate at temperatures below 1000 degrees C are important requirements. We demonstrate direct growth of defect-free graphene on insulators at moderate temperatures by molecular beam epitaxy. The quality of the graphene was probed by high-resolution Raman spectroscopy, indicating a negligible density of defects. The spectra are compared with those from graphene flakes mechanically exfoliated from native graphite onto mica. These results are combined with insights from density functional theory calculations. A model of graphene growth on mica and similar substrates is proposed.
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6. |
- Lippert, G., et al.
(författare)
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Molecular beam growth of micrometer-size graphene on mica
- 2013
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Ingår i: Carbon. - : Elsevier BV. - 0008-6223 .- 1873-3891. ; 52, s. 40-48
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate molecular beam growth of graphene on biotite mica substrates at temperatures below 1000 °C. As indicated by optical and atomic force microscopy, evaporation of carbon from a high purity solid-state source onto biotite surface results in the formation of single-, bi-, and multilayer graphene with size in the micrometer regime. It is shown that the graphene grown directly on mica surface is of very high crystalline quality with the defect density below the threshold detectable by Raman spectroscopy. The interaction between graphene and the mica substrate is studied by comparison of the Raman spectroscopy and atomic force microscopy data with the corresponding results obtained for graphene flakes mechanically exfoliated onto biotite substrates. Experimental insights are combined with density functional theory calculations to propose a model for the initial stage of the van der Waals growth of graphene on mica surfaces. This work provides hints on how the direct growth of high quality graphene on insulators can be realized in general without exceeding the thermal budget limitations of Si technologies.
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7. |
- Seifarth, O., et al.
(författare)
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Graphene directly grown on SiO2-based insulators
- 2011
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Ingår i: IEEE - Semicond. Conf. Dresden: Technol., Des., Packag., Simul. Test, SCD - Int. Conf., Workshop Table-Top Exhibit.. - 9781457704291
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Konferensbidrag (refereegranskat)abstract
- Strong effort is devoted to grow graphene directly on insulators to create a technological step towards cost effective mass production of high-frequency transistors on Si. We have shown recently, that direct graphene growth can be achieved on silicate substrates by solid carbon source deposition. Here, we present a study on the growth of graphene on insulator by means of Raman and photoelectron spectroscopy, corroborated by density functional theory calculations. We address temperature dependence and the correlation between graphene quality and the number of layers. We show that this approach may open a pathway to Si-compatible graphene growth for electronic applications.
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10. |
- Vaziri, Sam, et al.
(författare)
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An integration approach for graphene double-gate transistors
- 2012
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Ingår i: Solid-State Device Research Conference (ESSDERC), 2012 Proceedings of the European. - : IEEE. - 9781467317078 ; , s. 250-253
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Konferensbidrag (refereegranskat)abstract
- In this work, we propose an integration approach for double gate graphene field effect transistors. The approach includes a number of process steps that are key for microelectronics integration: bottom gates with ultra-thin (2nm) high-quality thermally grown SiO2 dielectrics, shallow trench isolation between devices and atomic layer deposited Al2O3 top gate dielectrics. The complete process flow is demonstrated with fully functional GFET transistors and can be extended to wafer scale processing and other graphene-based devices.
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