Regensburg 2010 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 61: Poster II: Materials, Interfaces and Heterostructures
HL 61.5: Poster
Thursday, March 25, 2010, 18:00–20:00, Poster D1
Lanthanide oxides thin films for graphene-based devices — •Ihor Petrov1, Teodor Toader1, Claudia Bock1, Ulrich Kunze1, Andrian Milanov2, Anjana Devi2, and Roland A. Fischer2 — 1Werkstoffe und Nanoelektronik, Ruhr-Universität Bochum — 2Anorganische Chemie II, Ruhr-Universität Bochum
We study the application potential of gadolinium and dysprosium oxide for graphene-based devices. Lanthanide oxide thin films of defined thickness are deposited in the presence of oxygen as well as nitrogen at 400 ∘C by thermal CVD on an n+-Si(100) substrate [1]. The roughness of the films is determined by atomic force micrographs and the thickness by cross-section scanning electron microscopy. A breakdown field in the range of 0.3 Vnm−1 is determined by I-V measurements for both rare earth oxides. From C-V measurements at 1 MHz the dielectric constant of Gd2O3 (єr = 9) and Dy2O3 (єr=8) are extracted. Since the dielectric constant of the rare earth oxides are higher compared to SiO2 we expect an improved screening of charged impurities [2] and therefore an improved performance for graphene-based devices due to the oxides. By using a Fresnel-law based model [3] the contrast of graphene is calculated as a function of wavelength for different oxide thicknesses and compared to optical and atomic force micrographs of exfoliated graphene on Gd2O3 and Dy2O3.
[1] A.P. Milanov, et al., Chemistry of Materials 21, 5443 (2009).
[2] S.V. Morozov, et al., Phys. Rev. Lett. 100, 016602 (2008).
[3] P. Blake, et al., Appl. Phys. Lett. 91, 063124 (2007).