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Actuation of thin polymeric films via electron irradiation is a promising avenue to realize devices based on strain engineered two-dimensional materials. Complex strain profiles demand a deep understanding of the mechanics of the polymeric layer under electron irradiation; in this article, we report a detailed investigation on electron-induced stress on a poly-methyl-methacrylate (PMMA) thin film material. After an assessment of stress values using a method based on dielectric cantilevers, we directly investigate the lateral shrinkage of PMMA patterns on epitaxial graphene, which reveals a universal behavior, independent of the electron acceleration energy. By knowing the stress-strain curve, we finally estimate an effective Young's modulus of PMMA on top of graphene, which is a relevant parameter for PMMA-based electron-beam lithography and strain engineering applications. Published under license by AIP Publishing.

Large scale, homogeneous quasi-free standing monolayer graphene is obtained on cubic silicon carbide, i.e. the 3C-SiC(111) surface, which represents an appealing and cost effective platform for graphene growth. The quasi-free monolayer is produced by intercalation of hydrogen under the interfacial, (6root3x6root3)R30-reconstructed carbon layer. After intercalation, angle resolved photoemission spectroscopy (ARPES) reveals sharp linear pi-bands. The decoupling of graphene from the substrate is identified by X-ray photoemission spectroscopy (XPS) and low energy electron diffraction (LEED). Atomic force microscopy (AFM) and low energy electron microscopy (LEEM) demonstrate that homogeneous monolayer domains extend over areas of hundreds of square-micrometers., 4 pages, 3 figures, Copyright (2011) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics

The morphology and structure of 3C-SiC(001) surfaces, grown on Si(001) and prepared via hydrogen etching, are studied using atomic force microscopy (AFM), low-energy electron diffraction (LEED), and Auger electron spectroscopy (AES). On the etched samples, flat surfaces with large terraces and atomic steps are revealed by AFM. In ultrahigh vacuum a sharp LEED pattern with an approximate (5×1) periodicity is observed. AES studies reveal a “bulklike” composition up to the near surface region and indicate that an overlayer consisting of a weakly bound silicon oxide monolayer is present.

The morphology and atomic structure of 4H–SiC(11¯02) and 4H–SiC(1¯102¯) surfaces, i.e., the surfaces found in the triangular channels of porous 4H–SiC, have been investigated using atomic force microscopy, low-energy electron diffraction (LEED), and Auger electron spectroscopy (AES). After hydrogen etching, the surfaces show steps parallel and perpendicular to the c axis, yet drastically different morphologies for the two isomorphic orientations. Both surfaces immediately display a sharp LEED pattern. Together with the presence of oxygen in the AES spectra, this indicates the development of an ordered oxide. Both surfaces show an oxygen-free well-ordered surface after Si deposition and annealing.