Extraction and scattering analyses of 2D and bulk carriers in epitaxial graphene-on-SiC structure

Li̇şesi̇vdi̇n, S. B.; Atmaca, G.; Arslan, Engin; Çakmakyapan, Semih; Kazar, Özgür; Bütün, Serkan; Ul-Hassan, Jawad; Janzén, Erik; Özbay, Ekmel

doi:10.1016/j.physe.2014.05.016

Cited by 7 publications

(2 citation statements)

References 46 publications

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“…As discussed above, the high substrate roughness is expected to produce local defects in the graphene, which may cause a similar effect, but more work is needed to further elucidate this phenomenon. Similarly, transport has also been observed in graphene on SiC due to parallel conduction in the 2D graphene and 3D SiC substrate 43 . We do not expect to see any contributions to electrical measurement from the BN/sapphire substrate due to the highly insulating nature of both BN and sapphire.…”

Section: Resultsmentioning

confidence: 74%

Wafer scale BN on sapphire substrates for improved graphene transport

Vangala

Siegel

Prusnick

et al. 2018

Sci Rep

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Wafer scale (2”) BN grown by metal organic chemical vapor deposition (MOCVD) on sapphire was examined as a weakly interacting dielectric substrate for graphene, demonstrating improved transport properties over conventional sapphire and SiO2/Si substrates. Chemical vapor deposition grown graphene was transferred to BN/sapphire substrates for evaluation of more than 30 samples using Raman and Hall effects measurements. A more than 2x increase in Hall mobility and 10x reduction in sheet carrier density was measured for graphene on BN/sapphire compared to sapphire substrates. Through control of the MOCVD process, BN films with roughness ranging from <0.1 nm to >1 nm were grown and used to study the effects of substrate roughness on graphene transport. Arrays of graphene field effect transistors were fabricated on 2” BN/sapphire substrates demonstrating scalability and device performance enhancement.

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Section: Resultsmentioning

confidence: 74%

Wafer scale BN on sapphire substrates for improved graphene transport

Vangala

Siegel

Prusnick

et al. 2018

Sci Rep

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“…This finding is very interesting considering that the samples with T Ar = 640 • C and 800 • C have better MLG coverage of 99% and lower RMS 0.4 nm, compared with the T Ar = 1300 • C sample, which has 92% MLG coverage and RMS 0.75 nm. It was previously suggested that dominant scattering mechanisms at room temperature in graphene on SiC are the remote interface phonon scattering, as a result of coupling to the polar modes in the substrate, and scattering by impurities [53][54][55]. Since the MLG samples are grown at the same T MLG and have similar history we do not anticipate difference in impurity levels.…”

Section: Free Charge Carrier Properties Of Mlg and Qfs-mlgmentioning

confidence: 84%

Critical View on Buffer Layer Formation and Monolayer Graphene Properties in High-Temperature Sublimation

Stanishev¹,

Armakavicius²,

Bouhafs³

et al. 2021

Preprint

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In this work we have critically reviewed the processes in high-temperature sublimation growth of graphene in Ar atmosphere using enclosed graphite crucible. Special focus is put on buffer layer formation and free charge carrier properties of monolayer graphene and quasi-freestanding monolayer garphene on 4H-SiC. We show that by introducing Ar at different temperatures, TAr one can shift to higher temperatures the formation of the buffer layer for both n-type and semi-insulating substrates. A scenario explaining the observed suppresed formation of buffer layer at higher TAr is proposed and discussed. Increased TAr is also shown to reduce the sp3 hybridization content and defect densities in the buffer layer on n-type conductive substrates. Growth on semi-insulating substrates results in ordered buffer layer with significantly improved structural properties, for which TAr plays only a minor role. The free charge density and mobility parameters of monolayer graphene and quasi-freestanding monolayer graphene with different TAr and different environmental treatment conditions are determined by contactless terahertz optical Hall effect. An efficient annealing of donors on and near the SiC surface takes place in intrinsic monolayer graphene grown at 2000∘C, and which is found to be independent of TAr. Higher TAr leads to higher free charge carrier mobility parameters in both intrinsically n-type and ambient p-type doped monolayer graphene. TAr is also found to have a profound effect on the free hole parameters of quasi-freestanding monolayer graphene. These findings are discussed in view of interface and buffer layer properties in order to construct a comprehensive picture of high-temperature sublimation growth and provide guidance for growth parameters optimization depending on the targeted graphene application.

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