Effects of the annealing and exposure on the optical and photoinduced properties of amorphous (As4S3Se3)1-x:Snx thin films

The influence of the heart treatment and light exposure on optical and photoinduced properties of (As4S3Se3)1-x:Snx thin films are investigated. The thin films were characterized by X-Ray diffraction (XRD), and optical absorption spectroscopy. The XRD measurements showed that the Sn impurities in the (As4S3Se3)1-x:Snx essentially don’t change the shape of he FSDP of the X-ray diffraction patterns, the intensity and the position of the first sharp diffraction peak non-monotoniously depend on the Sn concentration. By the optical absorption spectroscopy the transmission spectra of bulk materials and thin films of (As4S3Se3)1-x:Snx (x=0±10 at.%) in the visible and near infrared regions have been studied. The modifications of optical parameters (optical band gap Eg opt, absorption coefficient α, refractive index n) under light irradiation by halogen lamp of the amorphous thin films with different amount of Sn were measured and calculated. On the transmission spectra the red shift of the fundamental absorption edge under light exposure was observed, and the values of the optical band gap Eg opt from the graphics in Tauc coordinates (αhv)1/2=A(hv- Eg) were obtained. The dispersion of the refractive index was examined. Moreover, manifestation of partial reversibility of the optical absorption after annealing was demonstrated. The relaxation of the relative optical transmission T/T0=f(t) under the light exposure ( λ=633 nm) for amorphous (As4S3Se3)1-x:Snx thin films also was investigated. The relaxation curves of photodarkening under light irradiation were processing using the stretched exponential presentation of the data: T(t)/T(0) = A 0+Aexp[-(t-t0)/τ](1-b). Where t – is the exposure time, τ – is the apparent time constant, A – characterizes the exponent amplitude, t0 – and A0 – are the initial coordinates, and b- is the dispersion parameter (0<b<1), and were estimated by a computer program

Design of the Holographic Fiber-optic Electronic Speckle Pattern Interferometer for Optical Constants of Glasses Measurements

An elaboration the holographic fiber-optic electronic speckle pattern interferometer (ESPI) which can will be apply for measurement of the optical constants is described. This interferometer with CCD Smart Camera can be programming based on National Instruments’ graphical programming LabVIEW software. Using the LabVIEW we can apply flexible program for different software steps for processing of recorded interferograms (extracting amplitude, phase map and frequency domain, subtraction), obtained by CCD Smart Camera for feather calculation the optical properties the refractive index and thickness of studying samples

Characterization of high refractive amorphous (As4S3Se3)1-x:Snx chalcogenide glasses

The transmission spectra of bulk and thin films of (As4S3Se3)1-x:Snx in the visible and infrared (IR) regions were investigated. Doping of As4S3Se3 chalcogenide glass with Sn impurities essentially reduce the absorption bands of S-H (Se-H) and H2O located at ν=5190 cm-1 and ν=3617 cm-1, respectively. The amorphous (As4S3Se3)1-x:Snx thin films exhibit photoinduced effects under the light irradiation with photon energy above the optical band gap (hν≥Eg), that make its perspective materials for registration of optical and holographic information. The modification of optical parameters (optical band gap Eg, absorption coefficient α, refractive index n) under light irradiation and heat treatment of the amorphous thin films with different amount of Sn was studied

Raman scattering of Ge-As-Se thin films

Raman and infrared spectroscopy are efficient methods for obtaining information on the local structure of the disordered material, especially when the composition is varied. In particular, Micro-Raman spectroscopy have been used for study of the ternary glass system GexAsxSe1-2x, for which different composition in dependence of it mean coordination number Z exists in different phases - floppy, intermediate and stressed rigid. In this paper we report experimental results and analysis of Micro-Raman spectra for both thermally as-deposited and laser irradiated amorphous GexAsxSe1-2x (x=0.07; 0.09 and 0.14, Z=2.21; 2.27 and 2.42, respectively) thin films, of which glassy system situated in the region of floppy and intermediate phases. It was shown that for all investigated samples the measured Micro- Raman spectra consists from three vibrational modes located around ν=193 cm-1, ν=255 cm-1 and ν=475 cm-1. It was shown that position and intensity of these vibrational bands slightly depend on the composition and method of preparation. It was established that for Ge0.14As0.14Se0.72 composition with the mean coordination number Z=2.42, situated in the region of intermediate phase, the probability of existence of the tetragonal (pyramids As(Se1/2)3 and tetrahedral structural units Ge(Se1/2)4 is the same. For all samples of the glass composition Ge0.14As0.14Se0.72 the ratio of the intensity of both main vibration peaks centered around ν=193 cm-1 and ν=255 cm-1 remain unchanged

Light Induced Modification of the Refractive Index of Sb2Se3:Sn Thin Films

The optical properties of chalcogenide glasses present a great scientific interest for the establishment of the general legitimacy of interaction of the optical irradiation with the amorphous solids, as well as a practical interest. The effect of light-induced photostructural transformations in amorphous chalcogenides films have been initiated many applications of amorphous material in photonics and optoelectronics, especially as inorganic photo-resists for sub-micron technology. The optical parameters of amorphous Sb2Se3 and Sb2Se3:Snx (x=0.01, 0.5, 10 at. Sn %) prepared by vacuum evaporation on glass substrates was determined from transmission spectra. The band gap was found to be Eg=1.30 eV for amorphous Sb2Se3 and decrease with increasing of tin concentration up to Eg=1.0 eV for Sb2Se3:Sn10.0. For determination of the refractive index the approximation method proposed by Valeev was used. The maximum modifications of the refractive index under the light irradiation Δn ~ 0.20 occur for the composition Sb2Se3:Sn0.01. That allows us to conclude that doping of amorphous Sb2Se3 films with small concentrations of tin initiate the photostructural transformations under the light irradiation, and make these materials suitable for registration of optical and holographic information