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We investigated the physicochemicаl properties, structure and optical properties of the Ge25Ga9.5Sb0.5S65: Er3+/Yb3+ glasses. The Judd-Ofelt theory was used to calculate the intensities of the intra-4f electronic transitions of Er3+ ions. We observed the upconversion photoluminescence (UCPL) at 530, 550, 660 and 810 nm under 980 nm excitation. In the Ge25Ga9.5Sb0.5S65: 0.1 at.% Er3+, we found that the Stokes photoluminescence (PL) at the green spectral region excited by the 490 and 532 nm laser is only ≈5 times higher than the UCPL emission under 810 or 980 nm excitation making these materials attractive for UCPL applications. The addition of 0.1–1 at.% of Yb3+ into Ge25Ga9.5Sb0.5S65: 0.1 at.% Er3+ glass reduces the UCPL as well as the Er3+ ≈1.5 μm emission intensity probably due to the reabsorption processes of the excitation light and concentration quenching. However, the observed Er3+: 4 S 3/2→4 I 13/2 (≈850 nm) emission in the Ge25Ga9.5Sb0.5S65: 0.1 at.% Er3+ sample populates the 4 I 13/2 level, which promises the using of this material for the 1.5 μm optical amplification.

Doping of semiconductor quantum dots (QDs) by transition metals (such as Mn, Cu, Ni, etc.) is a great technique to impact the optical and structural properties of the host materials. The introduction of a small amount of impurity into the host semiconductor matrix leads to the shift of PL emission due to the change in the recombination process. The new emission pathways created by dopant influence the photoluminescence intensity, Stokes shift, lifetime and stability of QDs. Mn-doped ZnS QDs (1–15 mol. %) have been synthesized by the effective low-cost and nontoxic hot-injection method. N-phenylmorpholine-4-carbothioamide has been successfully applied as a novel source of sulfur in the synthesis of Mn-doped ZnS QDs. X-ray diffraction (XRD), scanning transmission electron microscopy (STEM) and infrared (IR) spectroscopy were used for the characterization of morphology and structure of synthesized Mn-doped ZnS QDs. Our materials exhibit strong photoluminescence yellow-orange emission with a photoluminescence quantum yield (PL QY) of 41%. All Mn-doped ZnS QDs have a face-centered cubic structure with a mean crystalline size of 3.8–5.1 nm. Additionally, this synthetic approach enables the synthesis of Mn-doped ZnS QDs with tunable band gaps between ∼3.5 eV and 3.60 eV.

We report on compositional tuning in Er3+ ions doped Ga–Ge–Sb–S glassy system allowing for effective 2H11/2→4I15/2 (530 nm), 4S3/2→4I15/2 (550 nm), 4F9/2→4I15/2 (660 nm), 4I9/2→4I15/2 (810 nm), 4I11/2→4I15/2 (990 nm) intra-4f electronic transition emissions of Er3+ ions under 808 nm, 980 nm or 1550 nm laser pumping. We changed the composition of well-known Ge20Ga5Sb10S65 glass to Ge25Ga10−xSbxS65, where x=0.5 at%, 2.5 at% or 5.0 at% and doped it with 0.5 at% of Er3+ ions. The short-wavelength absorption edge of the studied glassy hosts is blue-shifted by substitution of Sb with Ga to ~500 nm making the green emission at 530 nm and 550 nm and even 495 nm (4F7/2→4I15/2) observable, while the glass stability was kept high characterized with the difference of Tc−Tg>100 K and mean coordination numbers 2.67–2.71. Up-conversion emission decay times of all anti-Stokes emissions were in the range of 0.2–2.1 ms. The influence of Ga substitution with Sb on the structure and the optical properties was investigated. The spectroscopic parameters for Er3+ ions with local environment change were analyzed based on Judd–Ofelt theory.

The infrared emission properties of rare-earth (i.e., Dy 3+ , Pr 3+ or Sm 3+ ) and nickel-codoped Ge–Ga–Sb–S glasses were investigated by photoluminescence measurements. It was found that the emission intensities of the rare-earth doped glasses were significantly weakened even with very few amount of nickel (i.e., 500 at. ppm). On the other hand, the nickel-doped glasses show larger indices of refraction, which property will be desirable in nonlinear optics. Our results, however, suggest that to obtain rare-earth doped chalcogenide glasses of better infrared emission property it is necessary to keep the nickel dopant as low as possible.

Glasses of systems 100-y((GeS 2 ) 80 (Sb 2 S 3 ) 20− x (PbI 2 ) x )yPr 2 S 3 , x = 0; 2; 5, 8; y = 0; 0.01; 0.1; 0.5 and 99.9-z((GeS 2 ) 80 (Sb 2 S 3 ) 18 (PbI 2 ) 2 )0.1Pr 2 S 3 zYb 2 S 3 , z = 0.05; 0.1; 0.15) were synthesized in high purity. Optically well transparent glasses were obtained for x ⩽ 5 mol.% PbI 2 , for y ⩽ 0.1 mol.% Pr 2 S 3 and for z ⩽ 0.15 mol.% Yb 2 S 3 . The glasses were stable and homogeneous, as confirmed by X-ray diffraction and electron microscopy, with high optical transmittivity from visible (red) region up to infrared region (∼900 cm −1 ). The density of the glasses was 3.26–3.33 gcm −3 for PbI 2 containing glasses. The glass transition temperature, T g , was ∼320–336 °C. The optical absorption bands in rare-earth doped glasses corresponded to 3 H 4 – 3 F 4 , 3 H 4 – 3 F 3 , 3 H 4 –( 3 F 2 + 3 H 6 ) f–f electron transitions of Pr 3+ ions and to 2 F 7/2 – 2 F 5/2 f–f electron transitions of Yb 3+ ions. Strong luminescence band with maximum near 1340 nm (electron transition 1 G 4 – 3 H 5 ) was found in Pr 2 S 3 doped glasses. The intensity of this band was rising with doping by Yb 3+ ions. The possible mechanism of the luminescence enhancement is suggested.

International audience; Thermal, optical and electrical properties of the Agx(Ge28Sb12Se60)100x system (for x = 0 to 20) are systematically studied using various characterization techniques. In the present study, we have shown the reproducibility of the current results with the previously published literature and several novel results are also presented. The impedance data for the understanding of electrical properties of the materials has been analyzed using the random-walk (RW) model. We observed that, Ag playing two different concentration dependent roles i.e. above and below the 5% of Ag concentration, which is confirmed by the Raman analysis. The anomalous behaviors of electrical conductivity, optical and thermal properties with increasing Ag concentrations are explained by the role of Ag in the structural modification. We compared the diffusion coefficient (D), obtained from the RW model analysis with the experimental data(obtained from tracer diffusion) and found diffusion coefficient (D), obtained from the RW model are in good agreement corresponded with the experimental values. We also found a major change in conductivity of insulating Ge28Sb12Se60 (~ 10-14 S·cm-1) to a fast ionic conductor for Ag15(Ge28Sb12Se60)85 (~ 10-6 S·cm-1), i.e., a nine orders of magnitude. We demonstrated that the random-walk model can replacea time consuming and expensive tracer diffusion method for the determination of D. The present article helps to understand the ion conduction mechanism in disordered / amorphous materials.

Principles, advantages, applications and drawbacks of pulsed laser deposition (PLD) technique for thin films preparation are reviewed. The PLD method is promising for preparation of thin films of complex composition, including rare-earth and Ag-doped chalcogenide films; all components of the target can be evaporated at once. Low volatility and refractory materials can be also deposited. The deposition in vacuum, inert or reactive atmosphere is possible. Results obtained in a study of chalcogenide films are discussed and the current state-of-the-art is reviewed. The composition and structure of PLD films can be different from thermally evaporated films and new materials or materials with new properties applicable in optics and optoelectronics can be prepared. The method can be used for fabrication of different chalcogenide-based sensors and memory materials of complex composition. Photoinduced changes of structure and properties of PLD films and chalcogenides exposed to intense laser pulses are also discussed. The intense laser pulses can change the properties of the materials prepared and can be used for fabrication of chalcogenide-based waveguides, diffractive elements and high-density optical data storage media.

Pure and Sm 3+ doped amorphous thin films of Sb 2 S 3 were prepared by thermal co-evaporation of Sb 2 S 3 and Sm metal. The prepared films contained a slight over-stoichiometric excess of Sb. From transmittance measurement, the absorption edge, index of refraction, n , thickness, d , optical gap, E g opt , relative permittivity, e r , single oscillator energy, E o , dispersion energy, E d , and the values of third-order nonlinear susceptibility χ (3) were evaluated. The values of χ (3) increase with Sm doping. Some of above-mentioned values are slightly influenced by exposure of films to a UV lamp. The Raman spectra revealed two main structural units in the films: SbS 3 pyramids and Sb–Sb bonds in S 2 Sb–SbS 2 structural units. Three luminescence bands were found. The first one with maximum near 1130 nm can be assigned to 6 F 9/2 → 6 H 5/2 and/or 6 F 11/2 → 6 H 7/2 electron transitions, which are overlapping. The second band can be assigned to the electron transition 6 F 11/2 → 6 H 9/2 or 6 F 9/2 → 6 H 7/2 or 6 F 7/2 → 6 H 5/2 . The third luminescence band with maximum near 1500 nm can be probably assigned to the electron transition 6 F 11/2 → 6 H 11/2 .

High purity (GeS2)8−x (Sb2S3)20(NdCl3)x x=0, 0.01, 0.1, 0.5, glasses were prepared and their optical properties determined. The Ge-Sb-S system dissolves up to 0.5 mol.% of NdCl3 and still forms stable glasses. The structure of these glasses is formed by interconnected GeS4 tetrahedra and SbS3 pyramids as it follows from the Raman spectra. The glasses are optically well transparent in the range from 15400 cm−1 to 1000 cm−1. Doping with Nd creates new absorption bands which can be assigned to electron transfer from the 4 I 9/2 level to 2 G 5/2, 2 G 7/2, 2 H 11/2, 4 F 9/2, 4 F 7/2, 4 S 3/2, 2 H 9/2, 4 F 5/2, 4 F 3/2, 4 I 13/2 and 4 I 11/2 levels. The oscillator strengths and Judd-Ofelt parameters were evaluated. Their values are close to the values of those for Nd3+1 in another chalcogenide hosts. The long-wavelength absorption edge was found near 1000 cm−1 and is due to multiphonon Ge-S and Sb-S vibrations. In doped glasses, several broad luminescence bands near 890, 1080, 1370, and 1540 nm were found. They can be attributed to the transitions from 4 F 3/2 to 4 I 9/2, to 4 I 11/2, to 4 I 13/2 and 4 I 15/2 electron levels. The first luminescence band was excited also by 1064-nm line and represents probably the upconversion of light.

High purity (GeS2)80−x(Ga2S3)20·xNdCl3 (x=1, 2, 3) and (GeS2)79(Ga2S3)20·Nd2O3 glasses were prepared and their thermal and optical properties measured. The GeS2–Ga2S3 glasses can dissolve relatively large amounts of NdCl3 and Nd2O3 (≤3 mol%) and still form stable glasses. They are optically transparent in the range from 19000 cm−1 to 800 cm−1. The glass transition temperature (Tg≅378°C) and the glass-forming criteria are only slightly changed by Nd doping (ΔT=147°C, Hr=0.78; H′=0.39, S=4.10 K, where ΔT=Tc−Tg, Hr is Hruby's criterion, Hr=(Tc−Tg)/(Tm−Tc), H′=(Tc−Tg)/Tg, and S=(Tc−Tx)(Tc−Tg)/Tg). The short-wavelength absorption edge lies near 2.7 eV, doping with Nd creates new absorption bands which can be assigned to electron transfer from the 4 I 9/2 level to 4 G 7/2, 4 G 9/2, 2 K 13/2, 2 G 5/2, 2 G 7/2, 2 H 11/2, 4 F 9/2, 4 F 7/2, 4 S 3/2, 2 H 9/2, 4 F 5/2, 4 F 3/2, 4 I 15/2, 4 I 13/2 and 4 I 11/2 levels. In doped glasses, several broad luminescence bands, near 910, 1080 and 1360 nm, were found, which can be assigned to the transitions from 4 F 3/2 to 4 I 9/2, to 4 I 11/2 and to 4 I 13/2 electron levels. The long-wavelength absorption edge was found near 1000 cm−1 and is due to multiphonon Ge–S and Ga–S vibrations.

High purity (GeS2)80−x(Ga2S3)20·xPrCl3 (x= 1,2,3), (GeS2)79(Ga2S3)20Pr6O11 glasses were prepared and their basic thermal and optical properties were detemuned. The glass transition temperature Tg is in the region 399–404°C. The glass-forming criteria (ΔT ∈ (123–128°C), Hr ∈ (0.59–0.66), S ∈ (2.37–3.29) are changed by Pr doping only a little. The short-wavelength absorption edge lies near 2.7 eV, the doping by Pr creates new absorption bands which can be assigned to the 3H4-3H6, 3H4-3F3, 3H4-3F4, 3H4-3P0 and 3H4-3P1 electron transitions. The experimentally found oscillator strengths calculated from absorption spectra lies between those of Pr doped halide and chalcohalide glasses. The long-wavelength absorption edge was found near 800–1000 cm−1 and it corresponds to multiphonon Ge-S and Ga-S vibrations. The far-IR diffuse reflectance spectra were measured and the spectrum revealed by Kubelka-Munk method. The spectrum was deconvoluted into several bands which can be assigned to GeS4 and GaS4 tetrahedra vibrations. The narrow luminescence bands corresponding to electron transitions in Pr3+ ions (20000, 17857, 15873, 15220, 14326, 13947 and 13459 cm−1) with the most intensive band near 15220 cm−1 were found. These bands can be assigned to the transitions from the 3P0 and 1D2 levels to 3F4, 3F3, 3F2, 3H6, 3H5 and 3H4 levels. The most intensive band corresponds to the 3P0-3F2 transitions.

Er3+-doped Ge25Ga5Sb5S65 chalcogenide glass was studied as a potential material for up-conversion application to enhancement of silicon solar cell efficiency. Thermal properties were studied via DSC measurement, optical properties via variable angle spectroscopic ellipsometry and photoluminescence measurement. The host chalcogenide glass shows good thermal, chemical and physical properties. The band gap energy is ~2.23 eV which allows to emit green and red luminescent light from 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 4f-4f transitions of Er3+ ions under 800 nm pumping with Ti-sapphire tunable laser.

New glasses of composition 30 CdCl 2 - 50 PbCl 2 - 30 KI doped with 0.1; 0.5; 3; 5; 10; 15; 25 or 30 mol% PbO were prepared and their thermal (T g , T x , T c , T m ), and optical (T, R, diffuse reflectivity) properties from the visible to the far IR region were determined. The glass-forming ability is enhanced by doping with lead oxide and glasses of thickness up to 1 cm can be prepared. The glass transition temperature T g of investigated glasses is in the 84–120°C range, the temperature of crystallization T c is in the 122–146°C domain. The glasses are transparent from 22000 cm −1 up to 1000 cm −1 . The origin of IR absorption bands near 3450, 900 and 365 cm −1 is discussed.

The intense 1.32, 1.73, and 2.67 μm near-infrared and midinfrared emissions were observed from the Dy3+-doped GeSe2–Ga2Se3–MI (M=K, Cs, Ag) chalcohalide glasses. These glasses are red light transparent therefore can be pumped by a semiconductor lasers operating at ∼808 nm. The 2.67 μm emission has not been reported yet which corresponds to an absorption minimum in fluoride fibers and can be very useful for long distance communications. The intensity of emissions is very sensitive to the local chemical environment of Dy3+ ions embedded in these metal halide modified glasses. A plausible correspondence between the emission intensity and the average oscillator strength was found.

We report the kinetics of below band-gap light induced photodarkening in (80-x)GeS(2)-20Ga(2)S(3)-xAgI (x = 0 and 20 mol %) bulk chalcogenide glasses by measuring the time evolution of transmission spectra at every 10 milliseconds. The results prove clearly the enhancement of photosensivity upon doping of AgI compound in glasses. It is interesting to find that PD observed in AgI-doped glass totally disappears two hours later after the laser exposing even at room temperature. In significant contrast to 80GeS(2)-20Ga(2)S(3) glass that the metastable part of PD remains for a long time. We expect such a fast auto-recovery property in AgI-doped glass can be utilized for optical signal processing.

The intensity of two electron paramagnetic resonance signals with effective g -values of 2.0 and 4.3 was measured in the temperature region 4–40 K in Mn 2+ -doped halide glasses of the type CdCl 2 PbCl 2 KI and in chalcohalide glasses of the type GeS 2 Ga 2 S 3 MnCl 2 . The experimental ratio of the intensities of the two resonances in glasses with an Mn 2+ ion content lower than 1.0 mol% MnCl 2 was fitted to the ratio of the two Boltzmann distribution functions calculated with the spin-Hamiltonian parameters of the two magnetically active centers. Some type of exchange interaction was assumed to be present in the other glasses. This interpretation agrees with the experimental evidence of changes of the shape of the resonance signal as well as with the simulation of the intensity ratio curves.