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

Abstract Non-volatile phase-change materials with large optical contrast are essential for future tunable nanophotonic applications. Antimony trisulfide (Sb 2 S 3 ) has recently gained popularity in this field due to its low absorption in the visible spectral region. Although several Sb 2 S 3 deposition techniques have been reported in the literature, none of them was optimized with respect to stoichiometry, lowest possible absorption, and large refractive index contrast (Δ n ) upon the phase change. Here we present a comprehensive multi-parameter optimization of pulsed laser deposition of Sb 2 S 3 towards this end. We correlate the specific deposition with the resulting compositional and optical properties and report parameters leading to films with extraordinary qualities (Δ n = 1.2 at 633 nm). Additionally, we suggest crystal orientations and vibrational modes associated with the largest change in the refractive index and propose them as useful large-scale indicators of the Sb 2 S 3 switching contrast.