Ultra-low-resistivity nitrogen-doped p-type Cu2O thin films fabricated by reactive HiPIMS

• Ultra-low electrical resistivity below 5 × 10 −2 Ωcm was achieved. • High-energy regime of deposition is more suitable for fine doping of Cu 2 O by N. • Nitrogen molecules seems to be important for optoelectric properties of Cu 2 O:N. We have successfully fabricated the nitrogen-doped cuprous oxide thin films on the amorphous standard soda-lime glass by reactive high-power impulse magnetron sputtering. The energy of film-forming particles was controlled by the value of pulse-averaged target power density, which has a significant impact on the elemental composition, structure and optoelectrical properties of the films. We have shown that the high-energy regime is more suitable for preserving Cu 2 O structure and leads to continuous substitution of oxygen by nitrogen compared with the low-energy regime. Moreover, in the high-energy regime, it is possible, to some extent, to independently control the electrical resistivity and optical properties. The electrical resistivity decreases down to≈5 × 10 −2 Ωcm (upper bound of the hole mobility of 0.08 ± 0.05 cm 2 /Vs) at the optical band gap 2.0–2.3 eV. Special attention is paid to the formation of nitrogen molecules and their ability to form shallow acceptor states. Experimental results supported by our Density Functional Theory calculations indicate that N 2 replacing Cu in the Cu 2 O lattice is one possible (but not the only possible) acceptor. We have also found that the formation of nitrogen molecules is preferred in a high-energy regime