Copper Nitride Nanowire Arrays-Comparison of Synthetic Approaches.

Aleksandra Scigala,Marek Trzcinski,Marek Wiśniewski,Robert Szczesny,Tomasz Rerek,Edward Szłyk,Lukasz Skowronski

doi:10.3390/ma14030603

Aleksandra Scigala, Marek Trzcinski + Show 5 more

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https://doi.org/10.3390/ma14030603

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Journal: Materials	Publication Date: Jan 28, 2021
Citations: 8	License type: CC BY 4.0

Affiliation: Nicolaus Copernicus University, Institute of Physics

Abstract

Copper nitride nanowire arrays were synthesized by an ammonolysis reaction of copper oxide precursors grown on copper surfaces in an ammonia solution. The starting Cu films were deposited on a silicon substrate using two different methods: thermal evaporation (30 nm thickness) and electroplating (2 μm thickness). The grown CuO or CuO/Cu(OH)2 architectures were studied in regard to morphology and size, using electron microscopy methods (SEM, TEM). The final shape and composition of the structures were mostly affected by the concentration of the ammonia solution and time of the immersion. Needle-shaped 2–3 μm long nanostructures were formed from the electrodeposited copper films placed in a 0.033 M NH3 solution for 48 h, whereas for the copper films obtained by physical vapor deposition (PVD), well-aligned nano-needles were obtained after 3 h. The phase composition of the films was studied by X-ray diffraction (XRD) and selected area electron diffraction (SAED) analysis, indicating a presence of CuO and Cu(OH)2, as well as Cu residues. Therefore, in order to obtain a pure oxide film, the samples were thermally treated at 120–180 °C, after which the morphology of the structures remained unchanged. In the final stage of this study, Cu3N nanostructures were obtained by an ammonolysis reaction at 310 °C and studied by SEM, TEM, XRD, and spectroscopic methods. The fabricated PVD-derived coatings were also analyzed using a spectroscopic ellipsometry method, in order to calculate dielectric function, band gap and film thickness.

Highlights

Research related to copper nitride mainly concerned the deposition of thin films, especially by physical methods, such as radio frequency (RF) or direct current (DC) magnetron sputtering techniques [17,18,19,20], molecular beam epitaxy (MBE) [21] or pulsed laser deposition (PLD) [22,23]
We have developed a modified simple procedure for the fabrication of copper nitride nanowire arrays by the ammonolysis of copper(II) oxide films
The initially tested etching of silicon surfaces by HF/HNO3 solutions resulted in the non-uniform coverage of the substrate with metallic copper

Summary

Introduction

Metal nitrides have long been known for their unique physicochemical properties which have been exploited in various applications, for example, in electronics and optics, sensors, wear-resistant coatings and catalysis [1,2,3,4] Among this class of compounds, copper nitride (Cu3 N) has attracted significant attention in recent years due to its application in write-once optical recording media [5,6], spintronic systems [7] and electro-catalysis [8,9]. A significant increase in the number of new synthesis methods in the first decade of the 21st century was mainly related to the fabrication of Cu3 N nanoparticles by chemical methods [24] This allowed for the development of innovative, and potentially useful applications and possibilities for taking copper nitride as a base for new, more complex materials [8,25,26]. The fabrication of Cu3 N thin films using chemical deposition methods is still rare, and methods described in the literature include chemical vapor deposition (CVD), where copper(II) hexafluoroacetylacetonate (Cu(hfac)2 )

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