Thickness Optimization of Ultra-thin Nickel Films

  • Peter Wojdylo McMaster University


Ultrathin nickel films with thicknesses varying from 2-7nm in 1nm increments were produced using electron-beam physical vapor deposition. Optical transmittance spectra were obtained using ellipsometry and Fourier transform infrared spectroscopy, and resistivities were obtained by measuring sheet resistance using a four-point probe setup. The Haacke's figure of merit was used to determine the optimal thickness of 3nm for those films produced, and a relative slope method was used along with fits to obtained data to determine a more precise optimum of 3.3nm. Differences in transmittance and resistivity from other sources were attributed to the lesser degree of compacting in the deposition method used when compared to dc sputtering. The results show that nickel thin films can be optimized by thickness to produce transparent conductive electrodes for optoelectronic applications.


1Klaus Ellmer. Past achievements and future challenges in
the development of optically transparent electrodes. Na-
ture Photonics, 6(12):809, December 2012. ISSN 1749-4893.
doi:10.1038/nphoton.2012.282. URL
2D. S. Ghosh, L. Martinez, S. Giurgola, P. Vergani, and
V. Pruneri. Widely transparent electrodes based on ultra-
thin metals. Optics Letters, 34(3):325{327, February 2009.
ISSN 1539-4794. doi:10.1364/OL.34.000325. URL https://www.
3Luis Martnez, Dhriti Sundar Ghosh, Stefano Giurgola, Paolo
Vergani, and Valerio Pruneri. Stable transparent Ni elec-
trodes. Optical Materials, 31(8):1115{1117, June 2009. ISSN
0925-3467. doi:10.1016/j.optmat.2008.11.019. URL http://www.
4Frank L. Pedrotti, Leno Matthew Pedrotti, and Leno S. Pedrotti.
Introduction to optics. Pearson/Prentice Hall, Upper Saddle
River, N.J, 3rd ed edition, 2007. ISBN 978-0-13-149933-1.
5K. Fuchs. The conductivity of thin metallic lms according to
the electron theory of metals. Mathematical Proceedings of the
Cambridge Philosophical Society, 34(1):100{108, January 1938.
ISSN 1469-8064, 0305-0041. doi:10.1017/S0305004100019952.
6E.h. Sondheimer. The mean free path of electrons
in metals. Advances in Physics, 1(1):1{42, January
1952. ISSN 0001-8732. doi:10.1080/00018735200101151.
URL http://www-tandfonline-com.libaccess.lib.mcmaster.
7G. Haacke. New gure of merit for transparent conductors. Jour-
nal of Applied Physics, 47(9):4086{4089, September 1976. ISSN
0021-8979. doi:10.1063/1.323240. URL http://aip.scitation.
8Simon G Kaplan and Leonard M Hanssen. Silicon as a stan-
dard material for infrared re
ectance and transmittance from 2
to 5 m. Infrared Physics & Technology, 43(6):389{396, Decem-
ber 2002. ISSN 1350-4495. doi:10.1016/S1350-4495(02)00161-
5. URL
9Dhriti Sundar Ghosh. Basics of Ultrathin Metal Films and Their
Use as Transparent Electrodes. In Ultrathin Metal Transpar-
ent Electrodes for the Optoelectronics Industry, Springer Theses,
pages 11{32. Springer, Heidelberg, 2013. ISBN 978-3-319-00347-4
978-3-319-00348-1. URL
10.1007/978-3-319-00348-1_2. DOI: 10.1007/978-3-319-00348-
1 2.
10P. B. Johnson and R. W. Christy. Optical constants of transition
metals: Ti, V, Cr, Mn, Fe, Co, Ni, and Pd. Physical Review B, 9
(12):5056{5070, June 1974. doi:10.1103/PhysRevB.9.5056. URL
11M. L. Grilli, I. Di Sarcina, S. Bossi, A. Rinaldi, L. Pil-
loni, and A. Piegari. Ultrathin and stable Nickel lms as
transparent conductive electrodes. Thin Solid Films, 594
(Part B):261{265, November 2015. ISSN 0040-6090. doi:
10.1016/j.tsf.2015.05.015. URL http://www.sciencedirect.
12Bradley J. Pond, Tu Du, J. Sobczak, and Charles K.
Carniglia. Comparison of the optical properties of oxide
lms deposited by reactive-dc-magnetron sputtering with
those of ion-beam-sputtered and electron-beam-evaporated
lms. volume 2114, pages 345{355. International Society
for Optics and Photonics, July 1994. doi:10.1117/12.180926.
URL https://www-spiedigitallibrary-org.libaccess.lib.