Electrochemical direct writing and erasing of silver nanostructures on phosphate glass using atomic force microscopy

Abstract

This paper reports a liquid-free, mask-less electrochemical direct-write lithographic technique using an atomic force microscopy (AFM) probe for writing silver nanostructures in minutes on an optically transparent substrate. Under ambient conditions, silver is locally and controllably extracted to the surface of superionic (AgI) (AgPO) glass by bringing a conductive AFM probe tip in contact with it, biasing the probe with a negative voltage, and regulating the resulting current. The growth mechanism of the resulting nanostructure is explored by extracting silver with a stationary AFM tip on the surface of the silver. A moving tip was then used to produce continuous lines, solid films and discrete dots of silver by implementing continuous and pulsed current writing approaches. The line dimensions depend on writing speed and current flowing in the electrochemical circuit, while the size and spacing of the dots depend on the parameters (magnitude, duration and frequency) of the current pulses and the writing speed of the AFM tip. Line-widths in the ∼100 nm range are demonstrated. Our investigation also shows that a threshold potential must be overcome to be able to draw and reduce silver ions on the glass surface. When polarity between the electrodes is reversed, the patterned silver ionizes back into the glass, thus offering the capability to erase and rewrite Ag patterns on the glass surface.

Locally Controlled Cu-Ion Transport in Layered Ferroelectric CuInP2S6

“…An important question to ask is if the composition of the Cu-deficient CuInP 2 S 6 is formed by Cu 1+ depletion from the volume. While in RbAg 4 I 5 and (AgI) 0.25 (AgPO 3 ) 0.75 glasses, charge neutrality is fulfilled by replenishment of ions from the Ag counter electrode, , the bottom electrode used in this study is silver paint and does not provide Cu ions, ruling out a similar mechanism. Therefore, to maintain electroneutrality, extraction of Cu 1+ requires additional oxidation of the residual atoms in the lattice.…”

“…This mechanism was suggested as an SPM-based probe methodology for battery materials under the term of electrochemical strain microscopy (ESM). − Local electrodeposition driven by the current provided through the SPM tip resulting in additional material volume on the surface. This method has been shown for solid electrolytes used in Li-ion batteries − for irreversible processes and Ag-ion conducting solid electrolyte glasses where particle growth can be reversible. , …”

Toward Electrochemical Studies on the Nanometer and Atomic Scales: Progress, Challenges, and Opportunities

“…Cycling back to positive voltages reverses the particle formation, as indicated by displacement values close to 0 nm. The shape of the displacement curve indicates history dependence, with high values only occurring if preceding voltages are negative . The map of maximum displacement shown in Figure b highlights the difference in particle growth between CIPS (high values) and IPS (dark areas), indicating that the electrochemical reaction for particle growth involves Cu-ions and that the resulting particles are metallic Cu.…”

“…The shape of the displacement curve indicates history dependence, with high values only occurring if preceding voltages are negative. 92 The map of maximum displacement shown in Figure 7b highlights the difference in particle growth between CIPS (high values) and IPS (dark areas), indicating that the electrochemical reaction for particle growth involves Cu-ions and that the resulting particles are metallic Cu. Moreover, the observed displacement exhibits a pronounced dependence on temperature and frequency.…”

Nanoscale Mapping of Cu‐Ion Transport in van der Waals Layered CuCrP2S6

“…The high tolerance toward Cu vacancy encourages us to hypothesize that Cu ions can be eventually extracted out of the lattice and deposited on the surface, and an inverse tip bias is required to reinsert Cu ions into layers, which accounts for the reversible morphology change at low bias V tip ≤ −4 V. It should be noted that similar reversible volume change introduced by AFM tip is also observed in CIPS, [18] a well-studied Cu-ion conductor featuring the vary similar crystal structure with CCPS and in Ag-ion conductors, such as (AgI) 0.25 (AgPO 3 ) 0.75 . [34] For higher voltages, a complete removal of Cu ions may be obtained leading to a more complex electrochemical reaction. In short, the above results make us conjecture that Cu-ion diffusion kinetics go through a two-stage process www.advmatinterfaces.de by increasing tip bias: (I) Cu-ion migration reversibly across layers to form Cu-deficient intermediate phases Cu 1−x CrP 2 S 6 and small surface protrusions; (II) Cu-ion-transport-induced irreversible phase transition or even lattice collapse.…”