Pulsed laser deposition of Sb2S3 films for phase-change tunable nanophotonics

TL;DR

This paper optimizes pulsed laser deposition of Sb2S3 films to achieve minimal optical absorption and maximal phase-change contrast for tunable nanophotonics, identifying key parameters and material properties.

Contribution

It provides a comprehensive multi-parameter optimization of Sb2S3 deposition, correlating process parameters with optical properties and identifying indicators of high switching contrast.

Findings

Achieved films with Δn = 1.2 at 633 nm.

Correlated deposition parameters with optical contrast.

Identified crystal orientations linked to maximum refractive index change.

Abstract

Non-volatile phase-change materials with large optical contrast are essential for future tunable nanophotonics. Antimony trisulfide (Sb2S3) has recently gained popularity in this field due to its low absorption in the visible spectral region. Although several Sb2S3 deposition techniques have been reported in the literature, none of them was optimized with respect to the lowest possible absorption and largest optical contrast upon the phase change. Here, we present a comprehensive multi-parameter optimization of pulsed laser deposition of Sb2S3 towards this end. We correlate the specific deposition and annealing parameters with the resulting optical properties and propose the combination leading to films with extraordinary qualities ({\Delta}n = 1.2 at 633 nm). Finally, we identify crystal orientations and vibrational modes associated with the largest change in the refractive index and propose them as useful indicators of the Sb2S3 switching contrast.