Nanocomposites and nanomaterials 

Surface relief formation on As-S-Ge thin films after e-beam recording 

Revutska L.O.1, Shylenko O.I.2, Stronski A.V.3, Komanicky V.2, Bilanych V.S.4

1National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”. Prospect Peremohy 37, Kyiv-03056, Ukraine.
E-mail: liubov.revutska@gmail.com.

2Pavol Jozef Safarik University, Park Angelinum 9, Kosice-04001, Slovakia.

3V. Lashkaryov Institute of Semiconductor Physics of the NAS of Ukraine. 
Prospect Nauky 41, Kyiv-03680, Ukraine.

4Uzhgorod National University, Narodna Square 3, Uzhgorod-88000, Ukraine.

Chalcogenide glasses are promising materials with attractive properties, such as low losses and versatile photo-induced effects, which made them suitable candidates for production of gratings and other optical elements [1]. The interaction of these materials with the electron beam is of interest due to diversity of physical phenomena induced in chalcogenide films. 
The aim of this study is to investigate formation of surface relief on thermal evaporated As3S77Ge20 chalcogenide films after e-beam irradiation with different distances between irradiation dots and exposure doses.
Formed nanostructures with a height of approximately 100 nm were detected in As3S77Ge20 films after e-beam irradiation. The cones on the surface of films have Gaussian profiles. The exposure dose G varied from 12 mC·cm-2  to 12 C·cm-2.  The dependences of the height of surface nanostructures on the dose of irradiation were analyzed. It was shown that for G < 2400 mC·cm-2 the height of the surface relief gradually grows to 100-125 nm and for G > 2400 mC·cm-2, relief height decreases. The changing of shape and parameters of the obtained surface relief on As3S77Ge20 films can be explained by the charge model [2]. Charge relaxation time, and initial and inverse doses, and size of interaction region have been determined: τ1=(641,35 ± 110,42) ms, G0 = 9,60  mC·cm-2, Gi = 31,18 C·cm-2. 
These results show that As3S77Ge20 films can be used for fabrication of the optical elements. 

1.	A. V Stronski, M. Vlcek, A. Sklenar, P. E. Shepeljavi, and S. A. Kostyukevich. Application of As40S60-xSex layers for high-effciency grating production // J. Non. Cryst. Solids. - 2000. - Vol. 266–269. - P. 973–978.
2.	V. Bilanych et al. Surface pattering of Ge–As–Se thin films by electric charge accumulation // Thin Solid Films. 2016. - Vol. 616. - P. 86–94.