Dielectric Relaxation and Photo-electromotive Force in Ge-Sb-Te/Si Structures R. A. Castro-Arata 1 , M. A. Goryaev 1 , A. A. Kononov 1 , Y. Saito 2 , P. Fons 2 , J. Tominaga 2 , N. I. Anisimova 1 and A. V. Kolobov 1,2 1 Herzen State Pedagogical University of Russia, 191186, St. Petersburg, Russia 2 National Institute of Advanced Industrial Science & Technology, 305-8565, Tsukuba Central 5, 1-1-1 Higashi, Japan Keywords: Structures Ge-Sb-Te/Si, Dielectric Properties, Photovoltaic Effect. Abstract: The dielectric properties and photovoltaic effect spectra in the compositions of amorphous layers GeSb2Te4 (GST 124), Ge2Sb2Te5 (GST 225) и GeSb4Te7 (GST 147) applied on the monocrystallic silicon surface are investigated. It is shown that with a change in the GST composition, both the dielectric capacitivity and the frequency at which the maximum dielectric loss is observed change. It was found that the value of the change in photo-electromotive force is different for different layers: on samples with GST 124, the influence of amorphous layers is by an order of magnitude greater than for GST 225, and by 3 orders of magnitude greater than for GST 147. 1 INTRODUCTION Complex blend chalcogenide glassy semiconductors (CGSs) attract the attention of researchers in connection with their use in numerous devices of micro- and optoelectronics. For example, chalcogenide glassy semiconductors are currently used in the manufacture of thermal imaging systems (Cha, et al, 2012), fibers and transparent flat waveguides in the IR range (Snopatin, et al, 2009), in optical sensors (Charrier, et al, 2012) and nonlinear optics (Zhang, et al, 2015). Electrophysical and structural properties of chalcogenide semiconductors have been intensively studied recently (Siegrist, et al, 2011, Zhang, et al, 2012, Gabardi, et al, 2015), which is associated with their successful application in non-volatile memory devices (fiscal memory, phase-change memory). The principle of operation of such devices is based on a sharp change in the electrophysical properties of the material during a reversible phase transition between crystalline and amorphous states. Complex chalcogenides of the Ge-Sb-Te (GST) system are some of the most popular materials of fiscal memory (Kozyukhin, et al, 2014). The aim of this work is to establish the features of the dielectric relaxation spectra and photo- electromotive (photo-EMF) force in Ge-Sb-Te/Si structures based on GST layers obtained by HF magnetron sputtering. The study of the features of polarization processes in structures based on silver halides and chalcogenide glassy semiconductors, including photostimulated ones, allows to determine at what energy level the transport of charge carriers is carried out, distinguishing between zone and hopping mechanisms, and what is the nature of charge carriers, and also to evaluate a number of microscopic parameters of the studied compounds (Goryaev, 1997, 1998, Bordovskii, et al, 2001, Castro, et al, 2006, Anisimova, et al, 2010). 2 EXPERIMENTAL Thin films of the Ge-Sb-Te system (GeSb 2 Te 4 (GST 124), Ge 2 Sb 2 Te 5 (GST 225) и GeSb 4 Te 7 (GST 147)) with a thickness of the order of 50 nanometers were obtained by HF magnetron sputtering at room temperature on silicon substrates. The structural features of the samples were studied on a DRON-7 X- ray diffractometer. The obtained diffractograms (figure 1) measured at large 2θ scattering angles of X- rays in the range from 10° to 80° indicate the amorphous nature of the films under study. The elemental composition of the samples was studied 146 Castro-Arata, R., Goryaev, M., Kononov, A., Saito, Y., Fons, P., Tominaga, J., Anisimova, N. and Kolobov, A. Dielectric Relaxation and Photo-electromotive Force in Ge-Sb-Te/Si Structures. DOI: 10.5220/0009154201460150 In Proceedings of the 8th International Conference on Photonics, Optics and Laser Technology (PHOTOPTICS 2020), pages 146-150 ISBN: 978-989-758-401-5; ISSN: 2184-4364 Copyright c  2022 by SCITEPRESS – Science and Technology Publications, Lda. All rights reserved