Dependence of Nanostructure and the Optical Properties of Ni Thin Films with Different Thicknesses on the Substrate Temperature

Document Type: Research Paper

Author

Department of Mathematics and Physics, Science Faculty, Islamic Azad University Arak Branch, Arak, Iran

Abstract

Nickel films with the thicknesses of 30 and 120 nm were deposited on glass substrates, at different substrate temperatures (313 to 600 K) under uhv condition. The nano-structure of the films and mean diameter of grains was obtained for each films using atomic force microscopy (AFM). Their optical properties were measured by spectrophotometry in the spectral range of 190-2500 nm. Kramers-Kronig method was used for the analysis of the reflectivity curves. The Effective Medium Approximation (EMA) analysis was used to determine the values of volume fraction of voids (fv)and establish the relationship between the nanostructure of the film and EMA predictions. Qualitatively good agreements between structure Zone Model (SZM) as a function of substrate temperature and the values of (fv), is achieved. There is good agreement between these values and the results of mean diameter of grains for Ni films too. The absorption peaks of Ni thin films at ~ 1.4 eV and 5 eV are observed, with an additional bump at about 2 eV. The 1.4 eV peak is in particular much stronger than that obtained in earlier works on Ni thin films (Johnson and Christy (1974)) and on bulk Ni sample (Lynch et al (1971) and Ehrenrich et al (1963)). This is resulted from producing thin films under uhv condition. The conductivities  σ1 and σ2 calculated from  ɛ1 and ɛ2 for Ni films and were plotted vs energy.

Keywords


1. Potocnik J, Nenadovic M, Jokic B, Strbac S, Rakoeevic Z. Structural characterization of the Nickel thin film deposited by GLAD technique. Science of Sintering. 2013; 45: 61-67.
2. Kumar P. Magnetic behavior of surface nanostructured 50 nm Nickel thin films. Nano scale Res. Letters. 2010; 5: 1596-1602.
3. Song W K, Jing L, Podraza N J, Dickey E C. Spin spray-deposited Nickel manganite thermistor films for microbolometer applications. J. of the American Ceramic Society. 2011; 11: 516-523.
4. Otiti T, Ekosse G, Sathiaraj, Stephen T. Understanding Nickel Thin Film crystallization using X-Ray Diffractometry. J. Appl. Sci. Environ. Manage.. 2007; 11: 57-60.
5. Luo J K, Flewitt A J, Spearing S M, Fleck N A, Milne W I. Young’s modulus of electroplated Ni thin film for MEMS applications. Materials Letters. 2004; 58: 2306-2309.
6. Petrov I, Barna P B, Hultman L, Greene J E. Microstructural evolution during film growth. J. Vac. Sci. Technol.. 2003; A 21: S117-S128.
7. Thoronton J A. Structure and topography of sputtered coatings. J. Vac. Sci. Technol.. 1975; 12: 830-838.
8. Savaloni H, Bagheri-Najmi S. Characteristics of Cu and Zn films deposited on glass and stainless steel substrates at different substrate temperatures and angle of incidence. Vacuum. 2002; 66: 49-58.
9. Savaloni H, Player M A. Influence of deposition conditions and kind of substrate on the structure of uhv deposited Erbium films. Vacuum. 1995; 46: 167-179.
10. Savaloni H, Player M A, Gu E, Marr G V. Influence of substrate temperature,deposition rate, surface texture and material on the structure of uhv deposited Erbium films. Vacuum. 1992; 43: 965-980.
11. Grovenor C R M, Hentzell H T G, Smith D A. The development of grain structure during growth of metallic films. Acta Metall. 1984; 32: 773-781.
12. Hentzell H T G, Grovenor C R M, Smith D A. Grain structure variation with temperature for evaporated metal films. J. Vac. Sci. Technol.. 1984; A2: 218-219.
13. Messier R, Giri A P, Roy R A. Revised structure zone model for thin-film physical structure. J. Vac. Sci. Technol.. 1984; A2: 500-503.
14. Messier R. Toward quantification of thin film morphology. J. Vac. Sci. Technol.. 1986; A4: 490-495.
15. Lynch D W, Rosei R, Weaver J H. Infrared and visible optical properties of single crystal Ni at 4K. Solid State Commun.. 1971; 9: 2195-2199.
16. Roberts S. Optical properties of Nickel and Tungsten and their interpretation according to Drude's formula. Phys. Rev.. 1959; 114,: 104-115.
17. Ehrenreich H, Philipp H R, Olechna D J. Optical properties and Fermi surface of Nickel. Phys. Rev.. 1963; 131: 2469-2477.
18. Shiga M, Pells G P. The optical properties of Nickel above and below the Curie temperature. J. Phys. C (Solid St. Phys.). 1969; 2: 1847-1857.
19. Johnson R B, Christy R W. Optical constants of transition metals: Ti,V,Cr,Mn,Fe,Co,Ni and Pd. Physical Review. 1974; B9: 5056-5070.
20. Savaloni H, Khakpour A R. Substrate temperature dependence on the optical properties of Cu and Ag thin films. Eur. Phys. J. Appl. Phys. 2005; 31: 101-112.
21. Rosei R, Lynch D W. Thermomodulation spectra of Al,Au and Cu. Phys. Rev.. 1972; B5 : 3883-3894.
22. Maghazeii F, Savaloni H, Gholipour-Shahraki M. The influence of growth parameters on the optical properties and morphology of uhv deposited Ni thin films. Optics Commun. 2008; 281: 4687-4695.
23. Stoll M Ph. Optical properties of Nickel in the visible and near infra-red. Solid State Commun.. 1970; 8: 1207-1210.
24. Bruggemann D A G. Calculation of different physical constants of heterogeneous substances, dielectric constants and conductivities of the mixed bodies of isotropic substances. Ann. Phys. (Leipzig). 1935; 24: 636-664.
25. Aspnes E, Kinsbron E, Bacon D D. Optical properties of Au: sample effects. Phys. Rev.. 1980; B21: 3290-3298.