Ultra-Thin Silver Films obtained by Sequential Quench-Anneal Processing

TL;DR

This study demonstrates a two-step process involving quench condensing and annealing to produce ultra-thin, metastable silver films on glass, with a phase transformation at around 150K leading to metallic conductivity.

Contribution

It introduces a novel sequential quench-anneal method for growing ultra-thin silver films and characterizes the phase transformation during the process.

Findings

Precursor phase is insulating at low temperatures.

Reconstruction occurs near 150K, drastically reducing resistance.

Final film exhibits metallic behavior after annealing.

Abstract

We have used the two-step growth technique, quench condensing followed by an anneal, to grow ultra thin films of silver on glass substrates. As has been seen with semiconductor substrates this process produces a metastable homogeneous covering of silver. By measuring the in situ resistance of the film during growth we are able to see that the low temperature growth onto substrates held at 100 Kelvin produces a precursor phase that is insulating until the film has been annealed. The transformation of the precursor phase into the final, metallic silver film occurs at a characteristic temperature near 150K where the sample reconstructs. This reconstruction is accompanied by a decrease in resistance of up to 10 orders of magnitude.