Showing papers by "Joshua E. Goldberger published in 2013"
Ohio State University1, North Carolina State University2, Stanford University3, Pennsylvania State University4, Columbia University5, Northwestern University6, University of Texas at Austin7, University of Notre Dame8, Cornell University9, University of California, Berkeley10, Case Western Reserve University11
TL;DR: The properties and advantages of single-, few-, and many-layer 2D materials in field-effect transistors, spin- and valley-tronics, thermoelectrics, and topological insulators, among many other applications are highlighted.
Abstract: Graphene’s success has shown that it is possible to create stable, single and few-atom-thick layers of van der Waals materials, and also that these materials can exhibit fascinating and technologically useful properties. Here we review the state-of-the-art of 2D materials beyond graphene. Initially, we will outline the different chemical classes of 2D materials and discuss the various strategies to prepare single-layer, few-layer, and multilayer assembly materials in solution, on substrates, and on the wafer scale. Additionally, we present an experimental guide for identifying and characterizing single-layer-thick materials, as well as outlining emerging techniques that yield both local and global information. We describe the differences that occur in the electronic structure between the bulk and the single layer and discuss various methods of tuning their electronic properties by manipulating the surface. Finally, we highlight the properties and advantages of single-, few-, and many-layer 2D materials in...
4,123 citations
TL;DR: This material represents a new class of covalently terminated graphane analogues and has great potential for a wide range of optoelectronic and sensing applications, especially since theory predicts a direct band gap of 1.53 eV and an electron mobility ca.
Abstract: Graphene’s success has shown not only that it is possible to create stable, single-atom-thick sheets from a crystalline solid but that these materials have fundamentally different properties than the parent material. We have synthesized for the first time, millimeter-scale crystals of a hydrogen-terminated germanium multilayered graphane analogue (germanane, GeH) from the topochemical deintercalation of CaGe2. This layered van der Waals solid is analogous to multilayered graphane (CH). The surface layer of GeH only slowly oxidizes in air over the span of 5 months, while the underlying layers are resilient to oxidation based on X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy measurements. The GeH is thermally stable up to 75 °C; however, above this temperature amorphization and dehydrogenation begin to occur. These sheets can be mechanically exfoliated as single and few layers onto SiO2/Si surfaces. This material represents a new class of covalently terminated graphane analogue...
900 citations
TL;DR: TiSe2(en) is prepared by dissolution of Se powder and NaBH4 in en followed by injection of TiCl4 (1.5) as discussed by the authors. But this method is not suitable for high temperature environments.
Abstract: TiSe2(en) is prepared by dissolution of Se powder and NaBH4 in en followed by injection of TiCl4 (1.
12 citations
Patent•
01 Feb 2013TL;DR: In this paper, the authors describe compositions that contain a plurality of biocompatible selfassembling molecules that transform from isolated molecules or spherical micelles in the circulation into cylindrical nanofibers in the acidic extracellular environment of tumors which can be used to achieve a higher relative concentration of imaging, drug delivery, or radiotherapeutic agents at the tumor site compared to non-tumor tissues.
Abstract: Disclosed are compositions that contain a plurality of biocompatible self-assembling molecules that transform from isolated molecules or spherical micelles in the circulation into cylindrical nanofibers in the acidic extracellular environment of tumors which can be used to achieve a higher relative concentration of imaging, drug delivery, or radiotherapeutic agents at the tumor site compared to non-tumor tissues. This transition is rapid and reversible, indicating the system is in thermodynamic equilibrium.
2 citations
TL;DR: In this article, the growth of CaGe2 films on Ge(111) substrates by molecular beam epitaxy (MBE) and their subsequent conversion to germanane by immersion in hydrochloric acid was reported.
Abstract: Two-dimensional crystals are an important class of materials for novel physics, chemistry, and engineering. Germanane (GeH), the germanium-based analogue of graphane (CH), is of particular interest due to its direct band gap and spin-orbit coupling. Here, we report the successful co-deposition growth of CaGe2 films on Ge(111) substrates by molecular beam epitaxy (MBE) and their subsequent conversion to germanane by immersion in hydrochloric acid. We find that the growth of CaGe2 occurs within an adsorption-limited growth regime, which ensures stoichiometry of the film. We utilize in situ reflection high energy electron diffraction (RHEED) to explore the growth temperature window and find the best RHEED patterns at 750 {\deg}C. Finally, the CaGe2 films are immersed in hydrochloric acid to convert the films to germanane. Auger electron spectroscopy of the resulting film indicates the removal of Ca and RHEED patterns indicate a single-crystal film with in-plane orientation dictated by the underlying Ge(111) substrate. X-ray diffraction and Raman spectroscopy indicate that the resulting films are indeed germanane. Ex situ atomic force microscopy (AFM) shows that the grain size of the germanane is on the order of a few micrometers, being primarily limited by terraces induced by the miscut of the Ge substrate. Thus, optimization of the substrate could lead to the long-term goal of large area germanane films.
TL;DR: TiSe2(en) is prepared by dissolution of Se powder and NaBH4 in en followed by injection of TiCl4 (1.5) as mentioned in this paper. But this method is not suitable for high temperature environments.
Abstract: TiSe2(en) is prepared by dissolution of Se powder and NaBH4 in en followed by injection of TiCl4 (1.