Growth and characterization of flash-evaporated ferroelectric antimony sulphoiodide thin films

Abstract

Ferroelectric thin films of antimony sulphoiodide (SbSI) have been grown by flash evaporation in the thickness range of 0.1–1.5 μm. Annealing the films in a sulphur atmosphere at 100 °C for 10–12 min improved their stoichiometry and crystallinity. Structural studies revealed that films deposited normal to the substrate have a tendency to grow with the c axis oriented at 6° to the substrate. The refractive index and band gap estimated from the optical transmission curves for 1.0-μm-thick films were found to be 4 and 1.97 eV, respectively. The measured relative dielectric constant (ε′) for a 1.0-μm thick film at 100 KHz, 300 K was ∼73. Reproducible ferroelectric-to-paraelectric phase transitions were observed for films thicker than 0.2 μm.