Laser-induced piezoelectricity in AgGaGe_3–xSi_xSe₈ chalcogenide single crystals

¹ Faculty of Electrical Engineering, Czestochowa University of Technology, Armii Krajowej 17, 42-200 Czestochowa, Poland
² Department of Experimental Physics, University of Debrecen, Bem sq. 18/a, 4026, Debrecen, Hungary
³ Department of Chemistry, Eastern European National University, 13 Voli Avenue, 43025 Lutsk, Ukraine
⁴ Department of Inorganic and Organic Chemistry, Lviv National University of Veterinary Medicine and Biotechnologies, Pekarska Street 50, 79010 Lviv, Ukraine

^a e-mail: piorak2015@wp.pl

Received: 17 February 2015
Revised: 21 April 2015
Accepted: 5 May 2015
Published online: 9 June 2015

Abstract

Photoinduced changes of piezoelectric coefficients for novel chalcogenide AgGaGe_3–xSi_xSe₈ (x = 0.15, 0.3, 0.6, 0.9) single crystals are discovered. The measurements were performed during illumination by cw 532 nm laser (above energy band gap) with power about 400 mW. The relaxation after switching off of the laser beam was studied. Additional temperature dependences of piezoelectric diagonal tensor components were recorded to separate the thermal effect with respect to pure electronic contribution to the photoinduced piezoelectricity. In addition to the photoinduced piezoelectric effect FTIR spectra are studied in order to explore the influence of the thermal contribution. The photoinduced changes with taking into account of temperature contribution have achieved magnitude equal to approximately 50–60% for all the studied samples and the changes were found to be completely reversible. The possible mechanisms for the observed effects are discussed and additional quantum chemical DFT simulations for the principal structural fragments were performed.