Temperature dependence of energy band gap and spontaneous polarization of SbSI nanowires

For the first time temperature dependence of optical energy gap of antimony sulfoiodide (SbSI) nanowires has been determined. In ferroelectric phase (for 241 K < T < Tc = 292 K) the evaluated indirect forbidden optical energy gap has been fitted by EgfI(T) = [2.195(3) − 10.8(1) × 10−4T] eV. In paraelectric phase (Tc = 292 K < T < 344 K) the energy gap has been described by EgfI(T) = [2.152(4) − 9.3(1) × 10−4T] eV. It has been estimated that at the temperature of 240 K the spontaneous polarization of the SbSI nanowires has the maximum value of about 0.08 C/m2.

► First time temperature dependence of optical energy gap of SbSI nanowires has been determined.
► Mechanisms of optical absorption in SbSI have been discussed.
► Spontaneous polarization influences energy gap of SbSI nanowires near the Curie point.
► Temperature dependence of spontaneous polarization of SbSI nanowires has been evaluated.
► Optical properties of SbSI nanowires have been compared with data of bulk single crystals.