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We describe X-ray absorption spectroscopy (XAS) technique to probe the local structure of photo-induced phase. Photo-induced melting of chalcogenide glass (amorphous selenium, a-Se) was investigated. A grazing-incidence fluorescence excitation and a high efficiency X-ray detector were used to detect a small change of coordination number due to photo-induced transformation. It was shown that photo-induced three-fold coordinated sites are formed upon light irradiation forming cross-linking between selenium chains (photo-induced melting). A simple model is proposed which describes the reorientation of selenium chain perpendicular to the polarization direction of excitation light leading to photo-induced dichroism (anisotropy). Potential of XAS as a local probe of nanoscale structural modifications induced by photo-excitation is clearly demonstrated.

New chalcogenide semiconductors Cu₂NiSSe, Cu₂NiSeTe and Cu₂NiTe₂ with functional properties with partial substitutions Cu $\to$ Ni, S $\to$ Se $\to$ Te are synthesized. An analysis of the morphology and microcomposition of these compositions was carried out. The studies were carried out on a scanning electron microscope (SEM). During the analysis, it was found that the compositions were obtained in the form of polycrystals of sufficiently high purity determined by the percentage of elements in the samples. The formation of crystallites was determined depending on the metal and chalcogen atoms in the compositions. It has been established that the crystallites of the samples synthesized under vacuum conditions in these compositions have a size of $d\approx 300\mu$m.

Transmittance self-oscillation discovered in amorphous GeSe₂ films has attracted considerable interest, while its underlying mechanism remains controversial. We suggest that the oscillation is governed by at least two kinds of changes; one occurs in absorption for thin ($\sim 6\mu$m) films and the other in refractive-index for thick ($\sim 1$mm) plates. We also detail a model, which assumes recoverable micro-crystallization. An idea for increasing the oscillation frequency is proposed for possible applications.

As ammonium dihydrogen phosphate (ADP) is a popular nonlinear optical crystal, to engineer its linear and nonlinear optical properties, the chalcogenide compound cobalt sulphide (CoS) was doped and the crystals were grown by the slow solvent evaporation method. To increase the solubility of CoS in water, its nanoparticles were synthesized by wet chemical technique using ethylene diamine as the capping agent followed by microwave irradiation. The nanoparticle sample exhibited finite solubility in water and was used to dope in ADP crystals. The powder XRD patterns showed the single phase nature of the doped crystals. The FTIR spectra confirmed the presence of various functional groups and EDAX gave the estimation of Co and S elements. The EPR spectroscopy also confirmed the presence of cobalt in the doped samples. TGA indicated slightly less thermal stability of the doped crystals compared to the pure ADP. The dielectric study was carried out at room temperature in the frequency range from 100Hz to 1MHz. Also, various linear optical parameters were evaluated for pure and doped crystals using UV–Vis spectroscopy. The second harmonic generation (SHG) efficiency of Nd:YAG laser was evaluated by the Kurtz and Parry method for the doped samples, it was found to be slightly lesser than that of the pure ADP crystals.

Chalcogenide films can be used in thin-film solar cells due to their high photoelectric conversion efficiencies. It was difficult to identify one abnormal phase with high X-ray diffraction (XRD) intensity and preferred orientation in the samples for preparing chalcogenide films by spin-coating and co-reduction on soda-lime glass ($\mathrm{\text{Na}}{}_2\mathrm{\text{O}}\cdot \mathrm{\text{CaO}}\cdot 6{\mathrm{\text{SiO}}}_2$) substrates. The raw materials and reductant are metal chlorides and hydrazine hydrate respectively. In order to identify this phase, a series of experiments were done under different conditions. The phases of obtained products were analyzed by XRD and the size and morphology were characterized by scanning electron microscope (SEM) and atomic force microscopy (AFM). From the experimental results, first it was proved that the abnormal phase was water-soluble by water immersion experiment, then it was identified as NaCl crystal through XRD, energy dispersive spectrometer (EDS) and SEM. The cubic NaCl crystals have high crystallinity with size lengths of about 0.5–2$\mu$m and show a $<$100$>$ preferred orientation. The reaction mechanism of NaCl crystal was proposed as follows: The NaCl crystal was formed by reaction of Na₂O and HCl in a certain experimental conditions.

In recent years, chalcogenide glasses have emerged as a material platform for nonlinear signal processing and mid-infrared photonics. In addition, high Brillouin gain of these soft glasses enable compact and highly efficient Brillouin lasers (BL). We review recent progress on chalcogenide BL, compare fiber and waveguide laser geometries, and discuss the potential of chalcogenide platform for compact and high-coherence light sources.

We demonstrate the fabrication and nonlinear optical (NLO) characterization of chalcogenide glass thin films obtained from the solution phase driven approach. The characterization of the films was ahieved using FESEM, AFM, micro-Raman, FTIR, UV-Visible spectroscopy, optical profilometry and XRD. The NLO studies were performed on the solution driven and thermally deposited As₂S₃ films with $\sim$2ps, 800nm laser pulses using the Z-scan technique. The results obtained from AFM measurements demonstrated that the surface roughness of the film was considerably low ($\sim$2nm) and Z-scan data indicated that the nonlinear refractive index was in the 1.0–$11.0\times 10^{-18}$m²/W range.

In this paper, room temperature one-step electrodeposition of chalcogenide CZTS followed by annealing at different temperatures was studied. The scanning electron microscopy images of the deposits confirmed the presence of agglomerated particles in the deposits. The deposits annealed at ${400}^{\circ }$C did not show the presence of voids whereas deposits annealed at ${500}^{\circ }$C showed severe sulfur loss and were off-stoichiometric. Annealing at ${400}^{\circ }$C resulted in the deposits of compositions closer to the required ratio. Good absorbance over the entire visible range makes both the annealed deposits suitable absorber materials for thin-film photovoltaic cells. Current–voltage characteristics resulted in Ohmic trend and the slope of the plot increased with annealing temperature. The deposits showed good photosensitive behavior where resistance decreased upon shining the light source. The Mott–Schottky plot showed that the deposits were made of positively charged particles. CZTS thin film annealed at ${500}^{\circ }$C provided higher H₂ production rate (68.68 $\mu$mol ⋅ ${\text{g}}^{-1}$ ⋅ ${\text{h}}^{-1})$, which was 32 times higher than that of CZTS annealed at ${400}^{\circ }$C (2.08 $\mu$mol ⋅ ${\text{g}}^{-1}$ ⋅ ${\text{h}}^{-1})$. What’s more, photocatalytic activity of CZTS thin film remained 94% after 48 h which confirmed the good stability and reusability of CZTS thin film. CZTS thin film is a potential and durable candidate for photocatalysis.