Photoluminescence in Raman Scattering: Effects of HfO2 Template Layer on Ultrananocrystalline Diamond (UNCD) Films Grown on Stainless Steel Substrates
The growth of polycrystalline diamond films can play an important role in industry if they can be grown on industrially used materials like aluminum (Al) or stainless steel (SS). A critical issue related to the growth of ultrananocrystalline diamond (UNCD) thin films on metals like SS, in a Hydrogen rich environment like the one present during growth of UNCD films, is the diffusion of Hydrogen (H) into the SS substrate, as it has been observed in prior research, which results in hydride formation in the SS that induce brittleness in the SS substrate. Several interface layers have been proposed described to avoid the H diffusion into the SS. However, HfO2 has not been explored. The work reported here was focused on investigating the growth of UNCD films on commercially available SS substrates by using an interface layer of HfO2, which was found to be a good diffusion barrier for H to inhibit penetration into the SS substrate. The samples where characterized with SEM and Raman spectroscopy. A photoluminescence (PL) effect, observed in the Raman scattering analysis, is present in all the samples. The PL effect may be due to the interaction of the UNCD / HfO2 interface. and the SS substrate rather than UNCD film alone. The novel result from the experiments described here, is the fact that it is possible to grow UNCD films on unseeded HfO2 layers on SS substrates.
Keywords: Poly-crystalline diamond, photoluminescence, UNCD, Stainless Steel, Hafnium Dioxide
 Auciello, O. and A.V. Sumant, Status review of the science and technology of ultrananocrystalline diamond (UNCD™) films and application to multifunctional devices. Diamond and Related Materials, 2010. 19(7–9): p. 699-718.
 Kohmura, N., et al., Diamond growth on the high purity iron substrate using hotfilament CVD method. Diamond and Related Materials, 2005. 14(3): p. 283-287.
 Hirakuri, K.K., et al., Diamond growth in solid substrate from gaseous source. Journal of Applied Physics, 2004. 97(2): p. 023516.
 Sun, X., et al., Deposition of diamond coatings on Fe-based substrates with Al and Al/AlN interlayers. Surface and Coatings Technology, 2015. 284: p. 139-144.
 Chen, S., M. Gao, and R.P. Wei, Hydride formation and decomposition in electrolytically charged metastable austenitic stainless steels. Metallurgical and Materials Transactions A, 1996. 27(1): p. 29-40.
 Alcantar-Peña, J.J., et al., Science and technology of diamond films grown on HfO2 interface layer for transformational technologies. Diamond and Related Materials, 2016. 69: p. 221-228.
 Alcantar-Peña, J.J., et al., Low temperature hot filament chemical vapor deposition of Ultrananocrystalline Diamond films with tunable sheet resistance for electronic power devices. Diamond and Related Materials, 2016. 69: p. 207-213.
 Fuentes-Fernandez, E.M.A., et al., Synthesis and characterization of microcrystalline diamond to ultrananocrystalline diamond films via Hot Filament Chemical Vapor Deposition for scaling to large area applications. Thin Solid Films, 2016. 603: p. 62- 68.
 Yang, Q., C. Xiao, and A. Hirose, Plasma-enhanced deposition of nano-structured carbon films. Plasma Science and Technology, 2005. 7(1): p. 2660-2664.
 Steven, P. and J.N. Robert, Raman Spectroscopy of Diamond and Doped Diamond. Philosophical Transactions: Mathematical, Physical and Engineering Sciences, 2004. 362(1824): p. 2537-2565.
 Casiraghi, C., A.C. Ferrari, and J. Robertson, Raman spectroscopy of hydrogenated amorphous carbons. Physical Review B, 2005. 72(8): p. 085401.
 Adamopoulos, G., et al., Hydrogen content estimation of hydrogenated amorphous carbon by visible Raman spectroscopy. Journal of Applied Physics, 2004. 96(11): p. 6348-6352.
 Marchon, B., et al., Photoluminescence and Raman spectroscopy in hydrogenated carbon films. IEEE Transactions on Magnetics, 1997. 33(5): p. 3148-3150.
 Dychalska, A., et al., A Raman spectroscopy study of the effect of thermal treatment on structural and photoluminescence properties of CVD diamond films. Materials & Design, 2016. 112: p. 320-327.
 Birrell, J., et al., Interpretation of the Raman spectra of ultrananocrystalline diamond. Diamond and Related Materials, 2005. 14(1): p. 86-92.
 Hu, X.J., X.H. Chen, and J.S. Ye, The roles of hydrogen in the diamond/amorphous carbon phase transitions of oxygen ion implanted ultrananocrystalline diamond films at different annealing temperatures. AIP Advances, 2012. 2(4): p. 042109.
 Rastorguev, A.A., et al., Photoluminescence study of the electronic structure of HfO2 films. Journal of Structural Chemistry, 2008. 49(1): p. 21.