Kinetics of photo-dissolution within Ag/As2S3 heterostructure

TL;DR

This study investigates the photo-dissolution kinetics of silver in Ag/As2S3 heterostructures using optical and AFM techniques, revealing stage-dependent dissolution processes influenced by film thickness and laser dose, with different behaviors in various stacking configurations.

Contribution

It provides the first detailed kinetic analysis of Ag photo-dissolution in Ag/As2S3 heterostructures, highlighting the effects of film thickness, laser fluence, and stacking order.

Findings

Photo-dissolution occurs in three stages, dependent on Ag film thickness.

Higher laser fluence reduces the process to two stages.

Different stacking configurations show distinct dissolution behaviors.

Abstract

Chalcogenide glass-silver heterostructures are candidates for photoresist and diffractive optical applications. To optimize their processing, we report the kinetics of Ag photo-dissolution in As2S3 matrix using in-situ optical transmission/reflection measurements and real time atomic force microscopy (AFM) imaging under optical illumination. The results indicate that photodissolution occurs in three stages with the extent and kinetics of each stage depending strongly on Ag film thickness. By contrast, the photo-dissolution is found to be independent of As2S3 matrix thickness. The extent of three stages also depends strongly on the laser dose and can be reduced to two stages at higher laser fluence. A comparative study of two oppositely stacked sample configurations: As2S3/Ag/glass and Ag/As2S3/glass show that the heterostructures respond differently to light illumination. For the former, Ag dissolves completely into As2S3 matrix at a faster rate than for the latter case. The origin of this difference is established by energy dispersive X-ray spectroscopy and AFM measurements.