Copper atomic-scale transistors

Abstract

We investigated copper as a working material for metallic atomic-scale transistors and confirmed that copper atomic-scale transistors can be fabricated and operated electrochemically in a copper electrolyte (CuSO4 + H2SO4) in bi-distilled water under ambient conditions with three microelectrodes (source, drain and gate). The electrochemical switching-on potential of the atomic-scale transistor is below 350 mV, and the switching-off potential is between 0 and −170 mV. The switching-on current is above 1 μA, which is compatible with semiconductor transistor devices. Both sign and amplitude of the voltage applied across the source and drain electrodes (U bias) influence the switching rate of the transistor and the copper deposition on the electrodes, and correspondingly shift the electrochemical operation potential. The copper atomic-scale transistors can be switched using a function generator without a computer-controlled feedback switching mechanism. The copper atomic-scale transistors, with only one or two atoms at the narrowest constriction, were realized to switch between 0 and 1G 0 (G 0 = 2e2/h; with e being the electron charge, and h being Planck’s constant) or 2G 0 by the function generator. The switching rate can reach up to 10 Hz. The copper atomic-scale transistor demonstrates volatile/non-volatile dual functionalities. Such an optimal merging of the logic with memory may open a perspective for processor-in-memory and logic-in-memory architectures, using copper as an alternative working material besides silver for fully metallic atomic-scale transistors.

Ultralow‐Power Atomic‐Scale Tin Transistor with Gate Potential in Millivolt

“…A negative dc voltage of U DS is applied to the drain electrode. [ 12,13 ] When the U G > U DS , the gate electrode is the anode, and the combination of source and drain is the cathode. Some tin atoms on the surface of the gate are oxidized and dissolved as ions into the electrolyte: $$\[ \begin{array}{*{20}{c}}{{\rm{Sn}}({\rm{solid}}) \to {\rm{S}}{{\rm{n}}^{2 + }}({\rm{aq}}.)$$…”

“…A negative dc voltage of U DS is applied to the drain electrode. [12,13] When the U G > U DS , the gate electrode is the anode, and the combination of source and drain is the cathode. Some tin atoms on the surface of the gate are oxidized and dissolved as ions into the electrolyte:…”

“…[ 10 ] In this spirit, we have introduced atomic‐scale metallic transistors operated with a novel fundamental switching paradigm. [ 11–15 ]…”

“…[10] In this spirit, we have introduced atomicscale metallic transistors operated with a novel fundamental switching paradigm. [11][12][13][14][15] This paper demonstrates an atomic-scale tin transistor operated with an electrochemical potential applied to a gate. The required switching potential can be as low as 2.5 mV in magnitude, which is much lower than the minimal level on the supply voltage of a CMOS digital logic circuit set by Landauer's limit: [16] V DD ≥ 2(ln2)k B Te −1 = 35.8 mV, where k B is Boltzmann constant, T = 300 K, and e the electron charge, [17,18] and even smaller than the "action potentials" of neuron fire (−20−100 mV) in magnitude.…”

Multiplicity of atomic reconfigurations in an electrochemical Pb single-atom transistor

“…Only an electrochemical counter electrode (a Pb wire, 0.5 mm in diameter, 99.998% purity) is used here as a gate for the metallic atomic-scale transistor. A similar effort has been made for the operation of copper atomic-scale transistors [37]. The optical microscope image of the microelectrodes is shown in Fig.…”