The effect of heat treatment on structural and electronic properties of niobium nitride prepared by a thermal diffusion method

SURFACE & COATINGS TECHNOLOGY

卷:309

Article

Farha, Ashraf Hassan^1,2  Ozkendir, Osman Murat³  Elsayed-Ali, Hani E.¹  Myneni, Ganapati⁴  Ufuktepe, Yuksel⁵ 

[1] Old Dominion Univ, Appl Res Ctr, Dept Elect & Comp Engn, Norfolk, VA 23529 USA

[2] Ain Shams Univ, Dept Phys, Fac Sci, Cairo 11566, Egypt

[3] Mersin Univ, Tarsus Technol Fac, TR-33480 Tarsus, Turkey

[4] Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA

[5] Cukurova Univ, Dept Phys, TR-01330 Adana, Turkey

关键词: NbNX;    Nitride;    Surface morphology;    XRD;    Thermal diffusion;    XAS;   

DOI  :  10.1016/j.surfcoat.2016.11.044

来源: Elsevier

【 摘 要 】

Niobium nitride (NbNX) coatings were prepared onto Nb substrate by thermal diffusion at high temperatures. The formation of NbNX coating by thermal diffusion was studied in the range of 1250-1500 degrees C at constant nitrogen background gas pressure (1.3 x 10(-3) Pa) and processing time (180 min). The electronic and crystal structures of the NbNX coatings were investigated. It was found that nitrogen diffuses into Nb forming the Nb-N solid solution (bcc) alpha-NbN phase that starts to appear above 1250 degrees C. Increasing the processing temperature gives richer alpha-phase concentration. Besides, X-ray absorption spectroscopy (XAS) was performed to study the electronic structure of the NbNX layer. The results of the electronic structural study corroborate the crystal structural analysis. The Nb M-3,M-2 edge X-ray absorption spectroscopy (XAS) spectrum shows strong temperature dependence. At the highest processing temperature (1500 degrees C), the number of d holes increased. Electrostatic interaction between d electron and core hole was increased due to nitrogen diffusion into the niobium. For the studied conditions, only the alpha-NbN was observed in the X-ray diffraction patterns. (C) 2016 Elsevier B.V. All rights reserved.

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