Crystallization of Stoichiometric SbSI Glass

Abstract

Congruent crystallization of antimony sulphoiodide (SbSI) glass of stoichiometric composition, which is prepared successfully for the first time using rapid melt-quenching, has been investigated using differential scanning calorimetry (DSC). The results for glass powder show a glass transition at 127°C and two separate exothermal peaks with maxima around 140°C and 190°C. The ratio of the intensities of the exothermal peak at~190°C to the peak at~140°C increases as the particle size and heating rate are increased, but their total enthalpy remains constant at 62 ± 2 J/g for all DSC runs. Surface heating of the glass induced by a 520 nm CW laser shows two contracted regions: needle-like crystalline formations at low temperature and bulk crystallization at high temperature. The observed phenomena and DSC results suggest two different kinds of crystallization of the SbSI phase: one-dimensional crystallization at low temperature which starts from the sample surface and three-dimensional bulk crystallization that continues the transformation to crystalline state at higher temperatures. The origin of the two different crystallizations can be traced to the strong anisotropy of the SbSI crystal structure due to the weak van der Waals interaction between covalent-ionic chains (Sb 2 S 2 I 2 ) n .

In situ study of rotating lattice single‐crystal formation in Sb2S3 glass by Laue μXRD

“…During initial growth of the crystal line, we observe a transition from the crystal dot seed to the start of the crystal line where there is a gap in the indexed patterns. As reported previously, there is transition region between the seed crystal and the rest of the line that exhibits additional complexity. This region is prone to the formation of defects that can cause higher angle boundaries during crystallization, leading to undesirable additional grain formation as the growth front extends from the crystal seed to begin to form the line .…”

“…All crystals discussed in this paper were created at the optimal intensity of 8000‐8200 counts, which equates to a measured flux value of approximately 94.11 × 10 22 photons/s/m 2 . To determine whether sample temperature affects nucleation and/or crystallization, an Anton‐Paar DHS 900 heating stage was used to heat the samples up to 100°C, well below the Sb 2 S 3 crystallization temperature of 190°C …”

Formation of Ferroelectric Phases in Sb–S–I Glasses

“…Congruent crystallization of SbSI glass of stoichiometric composition (G1) was investigated previously, as described in Ref. The DSC and XRD measurements of powders of this composition of different sizes established one‐dimensional (1D) surface, and three‐dimensional (3D) bulk crystallizations, which corresponded to two separate exothermal peaks with maxima around 130°C–145°C and 190°C. For convenient reference, the DSC plots for two different particle sizes of G1 obtained at two heating rates are shown in Fig.…”

“…In our recent work, congruent crystallization of SbSI glass (G1) of stoichiometric composition was investigated by differential scanning calorimetry (DSC) and X‐ray powder diffraction (XRD) measurements . Maximum crystallization of SbSI was observed in two different temperature ranges around 140°C and 190°C for this glass with stoichiometric composition that lies outside of the glass‐forming region within the Sb–S–I system.…”

“…The growth of SbSI crystal in a direction normal to chains requires higher activation energy and hence begins only at higher temperatures. Then the SbSI crystalline grains would grow within volume [i.e., as three‐dimensional (3D) growth] in contrast to low‐temperature crystallization when they grow predominantly in length (1D) …”