Correlation between Material Properties, Crystalline Transitions, and Point Defects in RF Sputtered (N,Mg)-Doped Copper Oxide Thin Films

In the present work, we investigate the effects of N and Mg doping on the optical and electrical properties of Cu2O thin films deposited using radiofrequency magnetron sputtering at room temperature. Additionally, crystalline phases are studied through complementary X-ray diffraction and energy dispersive X-ray spectroscopy measurements. It is shown that nitrogen incorporation enhances both the electrical and optical properties, with resistivity reaching a value as low as 1.15 Omega cm and an average transmittance in the visible range of 31.74%. Raman spectroscopy measurements indicate an increase in the number of (N2)Cu shallow acceptor point defects, explaining the probed enhancement of p-type majority charge carriers. Also, in Mg-doped samples, marginal improvement of the optoelectrical properties is established. Conversely, we demonstrate that co-doping with Mg and N degrades the material crystallinity, leading to a reduction of thin film conductivity that could be attributed to high nitrogen incorporation. Subsequently, the influence of dopants on the electrical and optical properties is discussed via the analysis of the correlation between defects and Raman activities in the studied copper oxide thin films. This work contributes to the assessment of Mg and N as doping species, unveiling the dominant behavior of specific point defects. The results obtained in the study can therefore benefit future developments in copper-based p-type semiconducting oxides with enhanced optical and electrical properties.