The variation of the features of SnO 2 and SnO 2 :F thin films as a function of V dopant Gu ¨ven Turgut • Erdal So ¨nmez • Mehmet Yılmaz • M. Selim C ¸o ¨genli • Mu ¨cahit Yılmaz • U ¨ mit Turgut • Refik Dilber Received: 6 February 2014 / Accepted: 10 April 2014 / Published online: 20 April 2014 Ó Springer Science+Business Media New York 2014 Abstract V doped SnO 2 and SnO 2 :F thin films were suc- cessfully deposited on glass substrates at 500 °C with spray pyrolysis. It was observed that all films had SnO 2 tetragonal rutile structure and the preferential orientation depended on spray solution chemistry (doping element and solvent type) by X-ray diffraction measurements. The lowest sheet resistance and the highest optical band gap, figure of merit, infrared (IR) reflectivity values of V doped SnO 2 for ethanol and propane-2-ol solvents and V doped SnO 2 :F films were found to be 88.62 X–3.947 eV–1.02 9 10 -4 X -1 –65.49 %, 65.35 X–3.955 eV–8.54 9 10 -4 X -1 –72.58 %, 5.15 X– 4.076 eV–6.15 9 10 -2 X -1 –97.32 %, respectively, with the electrical and optical measurements. Morphological properties of the films were investigated by atomic force microscope and scanning electron microscope measure- ments. From these analysis, the films consisted of nano- particles and the film morphology depended on doping ratio/ type and solvent type. It was observed pyramidal, polyhedron, needle-shaped and spherical grains on the films’ surfaces. The films obtained in present study with these properties can be used as front contact for solar cells and it can be also one of appealing materials for other optoelec- tronic and IR coating applications. 1 Introduction Transparent conductive oxides (TCOs) are widespread used in the several technological devices [1]. There is an increasing attention in usage of TCO thin films in the field of conducting solar window materials [2], heat reflectors for solar applications [3], gas sensors [4], energy storage for Li- ion batteries and photo-electrode of dye-sensitized solar cells etc. because of their the low sheet resistance, good optical transmission and reflectance, chemically inert and mechanical rigidity [5, 6]. The stoichiometric tin oxide (TO- SnO 2 ), which is one of the first transparent conductors [5, 7], has a well insulator property, but it becomes n-type semi- conductor due to non-stoichiometry resulted from intrinsic defects (O vacancies or Sn interstitials) [8–10]. In order to treat some features of SnO 2 , many researches have focused on doping SnO 2 . The doping of the SnO 2 can be done by substituting Sn 4? and O 2- ions by dopant ions. Fluorine (F) and vanadium (V) are two of the most important anion and cation dopant elements [11, 12] because if V 5? and F - ions is replaced with Sn 4? and O 2- ions in SnO 2 structure, they will give two free electron to SnO 2 structure and so it is expected to increase electrical conductivity, optical trans- parency in visible region, and optical reflectance in infrared region. In earlier studies, there are a few studies on V doped SnO 2 thin films [13–20], therefore more detailed studies on V doped SnO 2 are necessary to identify V doping effect on the features of SnO 2 . G. Turgut (&)  E. So ¨nmez  U ¨ . Turgut  R. Dilber Department of Physics Education, Kazim Karabekir Education Faculty, Atatu ¨rk University, Erzurum 25240, Turkey e-mail: guventrgt@gmail.com; guventurgut@atauni.edu.tr G. Turgut  E. So ¨nmez  M. Yılmaz  M. S. C ¸o ¨genli Department of Nanoscience and Nanoengineering, Graduate School of Natural and Applied Sciences, Atatu ¨rk University, Erzurum 25240, Turkey M. Yılmaz Department of Science Teaching, Kazim Karabekir Education Faculty, Atatu ¨rk University, Erzurum 25240, Turkey M. Yılmaz Department of Physics Education, Education Faculty, Necmettin Erbakan University, Konya 42030, Turkey 123 J Mater Sci: Mater Electron (2014) 25:2808–2828 DOI 10.1007/s10854-014-1946-7