Synthesis of Copper Nitride Layers by the Pulsed Magnetron Sputtering Method Carried out under Various Operating Conditions

Abstract

Copper nitride shows various properties that depend on the structure of the material and is influenced by the change in technical parameters. In the present work, Cu–N layers were synthesized using the pulsed magnetron sputtering method. The synthesis was performed under different operating conditions: direct current (DC) or alternating current (AC) power supply, and various atmospheres: pure Ar and a mixture of Ar + N2. The structural properties of the deposited layers were characterized by X-ray diffraction measurements, and Raman spectroscopy and scanning electron microscopy have been performed. Optical properties were also evaluated. The obtained layers showed tightly packed columnar grain features. The kinetics of the layer growth in the AC mode was lower than that observed in the DC mode, and the layers were thinner and more fine-grained. The copper nitride layers were characterized by the one-phase and two-phase polycrystalline structure of the Cu3N phase with the preferred growth orientation (100). The lattice constant oscillates between 3.808 and 3.815 Å for one-phase and has a value of 3.828 Å for a two-phase structure. Phase composition results were correlated with Raman spectroscopy measurements. Raman spectra exhibited a broad, diffused, and intense signal of Cu3N phase, with Raman shift located at 628–635 cm−1. Studies on optical properties showed that the energy gap ranged from 2.17 to 2.47 eV. The results showed that controlling technical parameters gives a possibility to optimize the structure and phase composition of deposited layers. The reported changes were discussed and attributed to the properties of the material layers and technology method.

Power effect on the properties of copper nitride films as solar absorber deposited in pure nitrogen atmosphere

“…Table 1 summarised the values of the direct and indirect band energies obtained varying the RF power. They are very close to those found in the literature [9,23]. In the case of the samples deposited at 3.5 Pa, we observe a slightly blue-shift in the band gap energy as the RF power increases.…”

“…In addition, the films can show different properties depending on the technique used. Among the main methods used for the Cu 3 N deposition, we can find molecular beam epitaxy (MBE) [8], pulsed magnetron sputtering (PMS) [9], pulsed laser deposition (RPLD) [10], and reactive direct current (DC) magnetron sputtering [11] or reactive radio-frequency (RF) magnetron sputtering [12][13][14][15]. In this last case, the film stoichiometry and the properties can be easily changed.…”

Impact of the RF Power on the Copper Nitride Films Deposited in a Pure Nitrogen Environment for Applications as Eco-Friendly Solar Absorber

“…It is also preferred because of its great capability of scalability to large areas [ 4 ]; it is a reliable, robust and cost-effective technique that can be easily incorporated into an industrial production chain. In this sense, Cu 3 N films with different structural, optoelectronic properties have been already reported by modifying parameters such as the nitrogen fraction in the gas mixture, the power value, the type of substrate, the substrate-to-target distance and the substrate temperature, among others [ 23 , 29 , 30 , 31 ].…”

Power effect on the properties of copper nitride films as solar absorber deposited in pure nitrogen atmosphere

“…In this sense, chemical synthesis routes such as wet chemistry synthesis, solvothermal reactions of copper(II) chloride and sodium azide, [8] the formation of Cu 3 N films by using urea and a nitrogen source [9] and other methods like ultrasonic and microwave, [10] have been studied for several decades. In addition, physico-chemical fabrication methods have been also used for the Cu 3 N thin film deposition, for example, molecular beam epitaxy (MBE), [11] pulsed magnetron sputtering (PMS), [12] pulsed laser deposition (RPLD), [13] and reactive direct current (DC) magnetron sputtering [14] or reactive radio-frequency (RF) magnetron sputtering. [15][16][17][18] Among them, the technique that offers higher scalability to the PV industry and improved homogeneity in large areas is magnetron sputtering, being therefore preferred to the chemical synthesis routes.…”