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 spin–spin interactions between unpaired electrons in organic (poly)radicals, especially nitroxides, are largely investigated and are of crucial importance for their applications in areas such as organic magnetism, molecular charge transfer, or multiple spin labeling in structural biology. Recently, 2,2,6,6-tetramethylpiperidinyloxyl and polymers functionalized with nitroxides have been described as successful redox mediators in several electrochemical applications; however, the study of spin–spin interaction effect in such an area is absent.
Metallacarboranes with the shape of the Greek letter θ, such as [Co(C2B9H11)2]−, were tested, for the first time, as efficient photoredox catalysts in the oxidation of aromatic and aliphatic alcohols in water. Their efficiency is linked to their high solubility in water, their high oxidizing power (Co4+/3+), and their absence of fluorescence on excitation, among others.
We have investigated the radical functionalization of gold surfaces with a derivative of the perchlorotriphenylmethyl (PTM) radical using two methods: by chemisorption from the radical solution and by on-surface chemical derivation from a precursor.
A push–pull-functionalized stilbene has been prepared, with an electroactive perchlorotriphenylmethyl (PTM˙) radical and dimethylamine units as electron-withdrawing and -donating moieties, respectively, showing an electrocatalytic redox-induced Z → E isomerization where the open-shell nature of PTM˙ plays a key role in the isomerization ocurrance.
Probing nanoscale electrical properties of organic semiconducting materials at the interface with an electrolyte solution under externally applied voltages is key in the field of organic bioelectronics. It is demonstrated that the conductivity and interfacial capacitance of the active channel of an electrolyte‐gated organic field‐effect transistor (EGOFET) under operation can be probed at the nanoscale using scanning dielectric microscopy in force detection mode in liquid environment.