This work presents the optimization of the sputtering deposition of
Cu3N thin films using a N2 pure
environment, at RT and at different RF power values with the aim to
determine its suitability as optical absorber. XRD patterns reveal a
change in the preferred orientation from (100) to (111) as increasing
the RF power. Moreover, at RF power of 100 W and above, a
polycrystalline structure with the presence of several weak diffraction
peaks are obtained. From the chemical point of view, FTIR and Raman
measurements confirmed the presence of Cu-N bonds. From AFM images, it
is observed that thin films prepared at low RF power and 3.5 Pa show
very smooth surfaces. Finally, the direct and indirect band gap values
calculated are suitable for solar absorbers. Hence, these results
indicate that (i) the magnetron sputtering is an appropriate method to
fabricate this kind of material, and (ii) the depositions at low RF
power (up to 100 W) and N2 pressures of 3.5 Pa are
mainly preferred due to its smoother surfaces, its stoichiometry closer
to the required one, and suitable band gap energies that permit to use
this material as a potential absorber substitute of silicon.
This research has been supported by Grants PID2019-109215RB-C42 and
PID2019-109215RB-C43 funded by MCIN/AEI/ 10.13039/501100011033.
M.A. Rodríguez-Tapiador also acknowledge partial funding through MEDIDA
C17.I2G: CIEMAT. Nuevas tecnologías renovables híbridas, Ministerio de
Ciencia e Innovación, Componente 17 “Reforma Institucional y
Fortalecimiento de las Capacidades del Sistema Nacional de Ciencia e
Innovación”. Medidas del plan de inversiones y reformas para la
recuperación económica funded by the European Union – NextGenerationEU.
The authors would also like to thank A. Soubrie from Centro de
Microscopía Electrónica “Luis Bru” for her advice and AFM
measurements. Finally, A.L. Muñoz-Rosas is grateful to SECTEI México for
granted postdoctoral fellowship.