Resistive switching effect is observed for a gallium–indium/gallium oxide/graphene junction. The use of a gallium-based liquid metal (LM) alloy, in this case, the eutectic gallium–indium with its native gallium oxide skin, directly provides the metal top contact and the oxide layer needed to fabricate a memory.
Graphene is used as the bottom electrode due to its electrical properties and, importantly, because it prevents the formation of alloys, leading to a stable simple junction. With this structure, the ON/OFF ratio at 0.5 V between the high resistance state (HRS) and low resistance state (LRS) reached is ∼104 under ambient conditions. Deposition of an additional switching layer is not needed compared to other resistive random access memories [RRAMs], which makes this system less complex to fabricate. The migration of the oxygen atoms of the oxide layer would be intuitively considered the main reason for the modulation of the tunneling junction resistance, but we suggest that this is not the case and instead of that, charge trapping/detrapping at the very interface may dominate the switching function.
Tuneable and low cost molecular electronics
Resistive Switching Observation in a Gallium-Based Liquid Metal/Graphene Junction
Diego Gutiérrez, Jesús Alejandro de Sousa, Marta Mas-Torrent, and Núria Crivillers*
The dramatic consequences that the orientation adopted by the molecular dipoles, in diverse arrays of chloroaluminum phthalocyanine (ClAlPc) on Au(111), have on the ulterior adsorption and growth of C60 are explored by means of an all scanning probe microscopy approach. The unidirectional downwards organization of the molecular dipoles at the first layer reduces charge transfer from the metal to C60. Imbalance between attractive and repulsive interactions of the fullerenes are crucial for their ordered supramolecular aggregation.
To date, crystallization studies conducted in space laboratories, which are prohibitively costly and unsuitable to most research laboratories, have shown the valuable effects of microgravity during crystal growth and morphogenesis. Herein, an easy and highly efficient method is shown to achieve space-like experimentation conditions on Earth employing custom-made microfluidic devices to fabricate 2D porous crystalline molecular frameworks.
Layered group V transition-metal trichalcogenides are paradigmatic low-dimensional materials providing an ever increasing series of unusual properties. They are all based on the same basic building units, one-dimensional MX3 (M = Nb, Ta; X = S, Se) trigonal-prismatic chains that condense into layers, but their electronic structures exhibit significant differences leading to a broad spectrum of transport properties, ranging from metals with one, two, or three charge density wave instabilities to semimetals with potential topological properties or semiconductors.
A small library of 2,6- and 3,5-distyrenyl-substituted carborane-BODIPY dyes was efficiently synthesized by means of a Pd-catalyzed Heck coupling reaction. Styrenyl-carborane derivatives were exploited as molecular tools to insert two carborane clusters into the fluorophore core and to extend the π-conjugation of the final molecule in a single synthetic step.
A new compound formed by two antiparallelly disposed tetracyano thienoquinoidal units has been synthesized and studied by electrochemistry and several spectroscopic techniques. Its self-assembly on a Au(111) surface has been investigated by scanning tunneling microscopy.