Dresden 2011 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 85: Poster Session II

HL 85.42: Poster

Donnerstag, 17. März 2011, 18:00–21:00, P4

Temperature dependent transport measurements in quasi-freestanding graphene on SiC(0001) — •Epaminondas Karaissaridis¹, Sonja Weingart¹, Claudia Bock¹, Ulrich Kunze¹, Florian Speck², and Thomas Seyller² — ¹Werkstoffe und Nanoelektronik, Ruhr-Universität Bochum — ²Technische Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg

We report on magneto- and ballistic transport measurements in 2D Hall bars and 1D orthogonal cross junctions fabricated from quasi-freestanding monolayer graphene on SiC(0001).
The investigated films are produced by conversion of the (6√3×6√3)R30^∘ reconstruction into graphene via hydrogen intercalation [1]. The hole concentration of 6·10¹² cm⁻² and a mobility of 1900 cm²(Vs)⁻¹ are derived from Hall effect measurements at 2D structures. These values are constant in a temperature range of 1.4 K≤ T ≤ 300 K and correspond to a constant mean free path of l_e ≈ 50 nm. At T=1.4 K the bend resistance characteristic of the 1D orthogonal cross junctions (w = 50 nm) shows magnetic field dependent negative peaks indicating ballistic transport. As temperature is increased to T = 50 K a transition from the ballistic into the diffusive transport regime is observed. These results demonstrate that additional scattering in 1D systems plays an important role.

[1] F. Speck, et al., Mat. Sci. Forum 645-648, 629 (2010).