| SM ISO690:2012|
ACHIMOVA, Elena; STRONSKI, Alexander; PAIUK, Oleksandr; MESHALKIN, Alexei; LYTVYN, Oksana; PRISACAR, Alexandr; TRIDUH, Ghennadi. Peculiarities of surface relief formation in Ge5As37S58/Se nanomultilayers. In: Materials Science and Condensed Matter Physics. Editia a 7-a, 16-19 septembrie 2014, Chișinău. Chișinău, Republica Moldova: Institutul de Fizică Aplicată, 2014, p. 226.
|Materials Science and Condensed Matter Physics
Editia a 7-a, 2014
Conferința "Materials Science and Condensed Matter Physics" |
Chișinău, Moldova, 16-19 septembrie 2014
The chalcogenide glasses (ChG) as materials for recording media application are possessing unique characteristics such wide range of optical transparency, high refractive index and photostructural transformations, accompanied by the change of optical and chemical properties. The number of different photo-induced effects like photo-darkening and bleaching, local expansion or contraction, changes of the refractive index was shown for ChG thin films. Depending on the composition, their physical properties vary in a wide range. The properties and direct relief formation on As2S3–Se nanomultilayers was shown by Kikineshi . In present work the direct one-step relief formation with the use of amorphous chalcogenide multilayers of composition based on Ge5As37S58–Se was studied. Amorphous Ge5As37S58–Se nanomultilayers were prepared by computer driven cyclic thermal vacuum deposition from two isolated boats with Ge5As37S58 and Se on constantly rotated substrate at room temperature in one vacuum deposition cycle. The technology allows depositing thin films with thicknesses from 0.005 up to 3.0μm. The control of the thickness was carried out in-situ during the thermal evaporation by interference thickness sensor at λ= 0.95μm. Overlapping part of samples contains alternating nanolayers of Ge5As37S58 with thickness of 7nm and Se with thickness of 10nm. The total number of nanolayers was 200. Outside and internal rings of layers on the substrate contain pure compositions of Se and Ge5As37S58 consequently. Control layers of Se and Ge5 As37S58 were deposited at the same time onto the same substrate consequently through masks and used to check the composition and calculate the ratio of the sub-layer thicknesses in one modulation period. Resulting sample was Ge5As37S58 –Se multilayer structure with total thickness 1760 nm with the composition modulation period 17 nm. Optical transmission was measured in 200-900 nm optical range in order to determine the refractive index, thickness and optical band-gap energy of pure Ge5As37S58 and Se layers and Ge5As37S58 –Se multilayers. Diffraction gratings with 1 m period were recorded by two laser beams with s–s polarization (DPSS green laser, λ=532nm and power 100mW) with synchronous diffraction efficiency measurement by red laser (λ=650 nm) in first diffraction order. We have shown that diffraction efficiency of recorded grating is much more in Ge5As37S58 –Se multilayers (ten times as much) then in pure Ge5As37S58 due to relief grating formation. In the Ge5As37S58–Se system diffraction efficiency of 18% in absolute value was obtained at λ = 0.65 μm illumination wavelength. The surface relief of the gratings was investigated by atomic force microscopy (AFM). The application of Ge5As37S58 –Se multilayers lead to decrease in the time of holographic recording, i.e. to increase of holographic sensitivity by two times in comparison with Ge5As37S58 layer under similar conditions of holographic recording. Due to the changes in transmission, reflection, and in thickness under the influence of laser irradiation, Ge5As37S58 –Se multilayers may be used for effective amplitude-phase optical information recording, for the production of surface-relief optical elements.