In Situ Growth and Bias-Dependent Modification of NaBr Ionic Layers on Ag(111)

Bera, A. and Morgenstern, K.

Volume: 126 Pages: 10610-10617
DOI: 10.1021/acs.jpcc.2c03582
Published: 2022

Although the formation of insulating ionic layers on metal surfaces has been well studied, their growth mechanisms are still controversial. Here, we report several innovative approaches to trigger in situ growth to understand this growth mechanism. The modification of the layer and its in situ growth is followed by time-lapsed scanning tunneling microscopy at room temperature with atomic resolution. The NaBr molecules form bilayer and trilayer islands when deposited at room temperature. These stable layers begin to disintegrate when the voltage exceeds the threshold voltage during scanning. The molecules released from the modified layer subsequently attach to the preexisting layer in a predefined scan region. Scanning of two neighboring trilayer islands traps the mobile molecule between them, leading to their coalescence. Time-lapsed measurements offer a step-by-step realization of the in situ controlled growth of an ionic layer at the atomic scale. © 2022 American Chemical Society.

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