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The ongoing miniaturization of electronic devices has boosted the development of new post-silicon two-dimensional (2D) semiconductors, such as transition metal dichalcogenides, one of the most prominent materials being molybdenum disulfide (MoS2). A major obstacle for the industrial production of MoS2-based devices lies in the growth techniques. These must ensure the reliable fabrication of MoS2 with tailored 2D properties to allow for the typical direct bandgap of 1.9 eV, while maintaining large-area growth and device compatibility. In this work, we used a versatile and industrially scalable MoS2 growth method based on ionized jet deposition and annealing at 250 °C, through which a 3D stable and scalable material exhibiting excellent electronic and optical properties of 2D MoS2 is synthesized. The thickness-related limit, i.e., the desired optical and electronic properties being limited to 2D single/few-layered MoS2, was overcome in the thin film through the formation of encapsulated highly crystalline 2D MoS2 nanosheets exhibiting a bandgap of 1.9 eV and sharp optical emission. The newly synthesized 2D-in-3D MoS2 structure will facilitate device compatibility of 2D materials and confer superior optoelectronic device function.

Ultraviolet and X-ray photoelectron spectroscopies in combination with density functional theory (DFT) calculations were used to study the change in the work function (Φ) of graphene, supported by quartz, as induced by adsorption of hexaazatriphenylene-hexacarbonitrile (HATCN). Near edge X-ray absorption fine structure spectroscopy (NEXAFS) and DFT modeling show that a molecular-density-dependent reorientation of HATCN from a planar to a vertically inclined adsorption geometry occurs upon increasing surface coverage. This, in conjunction with the orientation-dependent magnitude of the interface dipole, allows one to explain the evolution of graphene Φ from 4.5 eV up to 5.7 eV, rendering the molecularly modified graphene-on-quartz a highly suitable hole injection electrode. © 2014 American Chemical Society., References: Novoselov, K.S., Jiang, D., Schedin, F., Booth, T.J., Khotkevich, V.V., Morozov, S.V., Geim, A.K., Two-Dimensional Atomic Crystals (2005) Proc. Natl. Acad. Sci. U. S. A., 102, pp. 10451-10453; Novoselov, K.S., Geim, A.K., Morozov, S.V., Jiang, D., Katsnelson, M.I., Grigorieva, I.V., Dubonos, S.V., Firsov, A.A., Two-Dimensional Gas of Massless Dirac Fermions in Graphene (2005) Nature, 438, pp. 197-200; Geim, A.K., Novoselov, K.S., The Rise of Graphene (2007) Nat. Mater., 6, pp. 183-191; Castro Neto, A.H., Guinea, F., Peres, N.M.R., Novoselov, K.S., Geim, A.K., The Electronic Properties of Graphene (2009) Rev. Mod. Phys., 81, pp. 109-162; Lee, C., Wei, X., Kysar, J.W., Hone, J., Measurement of the Elastic Properties and Intrinsic Strength of Monolayer Graphene (2008) Science, 321, pp. 385-388; Li, X., Cai, W., An, J., Kim, S., Nah, J., Yang, D., Piner, R., Tutuc, E., Large-Area Synthesis of High-Quality and Uniform Graphene Films on Copper Foils (2009) Science, 324, pp. 1312-1314; Li, X., Zhu, Y., Cai, W., Borysiak, M., Han, B., Chen, D., Piner, R.D., Ruoff, R.S., Transfer of Large-Area Graphene Films for High-Performance Transparent Conductive Electrodes (2009) Nano Lett., 9, pp. 4359-4363; Salzmann, I., Moser, A., Oehzelt, M., Breuer, T., Feng, X., Juang, Z.-Y., Nabok, D., Heimel, G., Epitaxial Growth of π-Stacked Perfluoropentacene on Graphene-Coated Quartz (2012) ACS Nano, 6, pp. 10874-10883; Li, Y., Liu, C., Tong, S., Pan, L., Pu, L., Minari, T., Tsukagoshi, K., Shi, Y., Metal-Diffusion-Induced ITO Nanoparticles at the Organic/ITO Interface (2012) J. Phys. D: Appl. Phys., 45, p. 165104; Koch, N., Duhm, S., Rabe, J.P., Vollmer, A., Johnson, R.L., Optimized Hole Injection with Strong Electron Acceptors at Organic-Metal Interfaces (2005) Phys. Rev. Lett., 95, p. 237601; Coletti, C., Riedl, C., Lee, D.S., Krauss, B., Patthey, L., Von Klitzing, K., Smet, J.H., Starke, U., Charge Neutrality and Band-Gap Tuning of Epitaxial Graphene on SiC by Molecular Do

Ultraviolet and X-ray photoelectron spectroscopies in combination with density functional theory (DFT) calculations were used to study the change in the work function (Phi) of graphene, supported by quartz, as induced by adsorption of hexaazatriphenylene-hexacarbonitrile (HATCN). Near edge X-ray absorption fine structure spectroscopy (NEXAFS) and DFT modeling show that a molecular-density-dependent reorientation of HATCN from a planar to a vertically inclined adsorption geometry occurs upon increasing surface coverage. This, in conjunction with the orientation-dependent magnitude of the interface dipole, allows one to explain the evolution of graphene (Phi) from 4.5 eV up to 5.7 eV, rendering the molecularly modified graphene-on-quartz a highly suitable hole injection electrode.

Ultraviolet and X-ray photoelectron spectroscopies in combination with density functional theory (DFT) calculations were used to study the change in the work function (Phi) of graphene, supported by quartz, as induced by adsorption of hexaazatriphenylene-hexacarbonitrile (HATCN). Near edge X-ray absorption fine structure spectroscopy (NEXAFS) and DFT modeling show that a molecular-density-dependent reorientation of HATCN from a planar to a vertically inclined adsorption geometry occurs upon increasing surface coverage. This, in conjunction with the orientation-dependent magnitude of the interface dipole, allows one to explain the evolution of graphene (Phi) from 4.5 eV up to 5.7 eV, rendering the molecularly modified graphene-on-quartz a highly suitable hole injection electrode.