Robust, Transparent Hybrid Thin Films of Phase-Change Material Sb₂S₃ Prepared by Electrophoretic Deposition

Abstract

Thin films of polyethyleneimine-stabilized Sb2S3 are prepared via electrophoretic deposition (EPD), showing strong adhesion between deposited layers and underlying substrate, with the films being crystallized via annealing. For amorphous films, thicknesses can be freely tuned from 0.2-1 μm, shrinking to 0.1-0.5 μm when crystallized, whilst retaining a crack-and defect-free surface, thus not impacting on their good stability, and maintaining their optical properties. Through UV-Vis spectroscopy and subsequent modelling of the obtained spectra, it was concluded that the materials after annealing showed a reduced band gap and a demonstrably increased refractive index (n) and carrier concentration. The use of EPD for this material shows the viability of rapidly creating stable thin films of phase-change materials.

Interlaboratory study on Sb2S3 interplay between structure, dielectric function, and amorphous-to-crystalline phase change for photonics

“… (C) Statistical variation of the energy-dependent behavior of the real, ε 1 , and imaginary, ε 2 , parts of the a-Sb 2 S 3 dielectric function. (D) Refractive index, n , and extinction coefficient, k , of a-Sb 2 S 3 also compared with the data in literature ( Delaney et al., 2020 ; Dong et al., 2019 ; Hassam et al., 2021 ). …”

“… (B) Refractive index contrast between amorphous and Type-I and Type-II crystallized Sb 2 S 3 . (C) Refractive index n , and extinction coefficient, k , for Type-I and Type-II c-Sb 2 S 3 compared with values from literature ( Delaney et al., 2020 ; Dong et al., 2019 ; Hassam et al., 2021 ). (D) Refractive index contrast between amorphous and Type-I and Type-II c-Sb 2 S 3 also compared with values from literature ( Delaney et al., 2020 ; Dong et al., 2019 ; Hassam et al., 2021 ).…”

“… (C) Refractive index n , and extinction coefficient, k , for Type-I and Type-II c-Sb 2 S 3 compared with values from literature ( Delaney et al., 2020 ; Dong et al., 2019 ; Hassam et al., 2021 ). …”

“… (D) Refractive index contrast between amorphous and Type-I and Type-II c-Sb 2 S 3 also compared with values from literature ( Delaney et al., 2020 ; Dong et al., 2019 ; Hassam et al., 2021 ). …”

“…Sb 2 S 3 synthesis over large area has been reported using a wide range of methods including chemical bath deposition ( Kondrotas et al., 2018 ; Cobianu et al., 2021 ), electrophoretic deposition ( Hassam et al., 2021 ), atomic layer deposition ( Kim et al., 2014 ) and RF sputtering ( Gao et al., 2019 ). In the 1990s, Sb 2 S 3 was widely studied for write-once-read-many times (WORM) optical storage applications, as problems related to sulfur loss upon phase change leading to film degradation were reported ( Arun and Vedeshwar, 1996 , 1997 ).…”