Regensburg 2013 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 28: Poster Session: Graphen; Transport properties; Transport in high magnetic fields / Quantum Hall effect; Metal-semiconductor hybrid systems

HL 28.13: Poster

Montag, 11. März 2013, 16:00–20:00, Poster A

Acoustic charge transport in epitaxial graphene on SiC — •Paulo V. Santos, Timo Schumann, Myriano H. Oliveira Jr., Joao Marcelo J. Lopes, and Henning Riechert — Paul-Drude-Institut für Festkörperelektronik, Berlin, Germany

Graphene is emerging as an important material for electronic applications due to its high carrier mobility. Here, we investigate carrier control in epitaxial graphene on SiC (epiG) using dynamic strain field produced by a surface acoustic wave (SAW). The strain field periodically modulates the epiG band structure[1]. Electron beam collimators based on this effect have been proposed [2]. We report on the piezoelectric excitation and on acoustic charge transport by SAWs in epiG. SAWs with GHz frequencies were generated by interdigital transducers (IDTs) fabricated on a piezoelectric ZnO island on semi-insulating SiC. These SAW frequencies are substantially higher than those reported for acoustic transport in graphene flakes[3]. Acoustic transport studies in a Hall bar geometry show that SAWs transport carriers in epiG, with the transport direction being determined by the direction of the acoustic beam. The mechanisms for the carrier transport, including the effects of the strain field and the weak piezoelectric field in SiC will be discussed.

[1] C.-H. Park et al., Phys. Rev. Lett., 101, 126804 (2008).

[2] C.-H. Parket al., Nano Lett., 8 2920 (2008).

[3] V. Miseikis et al., Appl. Phys. Lett., 100, 133105 (2012).