Modification of atomic structure of thin amorphous V2O5 films under UV laser irradiation
Cheremisin, Alexander1; Putrolainen, Vadim1; Loginova, Sveta1; Pergament, Alexander1; Grishin, Alexander2; Velichko, Andrey1
1Russian Federation;
2Sweden

Investigation of the influence of laser radiation on the properties of transition metal oxide amorphous films is of importance due to an applied potentiality [1]. Thin films of amorphous V2O5 were synthesized by the pulse laser deposition technique described in detail in [2]. Modification of amorphous oxide films was performed with a KrF excimer laser (COMPEX-102) at a wavelength of 248 nm, pulse duration 20 ns, and energy density in a pulse ~ 75 mJ/cm2. X-ray diffraction study of initial and modified films on glass substrates was performed using an automated diffractometer DRON-3.0 with MoKα radiation in the angle range from 5° to 50° in asymmetrical configuration. Samples were set at angle of 5°. Normalization of the distribution curves of amorphous oxide film intensity dispersion was made, as well as calculations of an s-weighted interference function and the pair function distribution by means of an approved method described in detail in [3]. Calculations of the short-range order characteristics (radii and diffusiveness of coordination spheres, coordination numbers) were performed by the Finbak -Warren method [3]. The analysis of the quantity specifications of short order of initial and modified films shows that a minimum structure unit of the studied amorphous oxide films is a strongly distorted oxygen octahedron. The distortion of tetragonal pyramids in amorphous oxides is less than that in the crystalline phase of V2O5. It should be noted however that the character of the tetragonal pyramid distortions in the initial and modified films is different. Also, these pyramids (first coordination polyhedrons) are oxygen deficient. This work was supported by Svenska Institutet (Dnr:01370/2006), US CRDF grant (award No. RUX0-000013-PZ-06) and by Ministry of Education of Russian Federation. [1] Chudnovskii, F.A., Kikalov, D.O., Pergament, A.L., Stefanovich, G.B. // Physica Status Solidi A. V.172. N.2.1999. P. 391. [2] Putrolainen V.V., Cheremisin A.B., Velichko A.A., Pergament A.L., Stefanovich G.B., Grishin A.M. // V Int. Conf. "AMS". Proc. St. Petersburg. 2006. P. 285. [3] Mozzi, R. L., Warren, B. E. // J. Appl. Cryst. V.3. N.2. 1970. P.251.
back