Contribution of enhanced ionization to the optoelectronic properties of p-type NiO films deposited by high power impulse magnetron sputtering.

Herein, intrinsic p-type conductivity of NiO films were enhanced by high power impulse magnetron sputtering (HiPIMS) technology, where more charged Ni3+ ions are created during the deposition process. The formation of Ni3+ ions are advantageous for strengthening the p-type conductivity of NiO films. As the pulse off-time increases from 0 μs to 3000 μs, Ni3+ concentration improves greatly, indicating the amount of Ni vacancies as well as the hole concentration significantly enhances. It confirms that HiPIMS is a preferential technology for preparing NiO films with high p-type conductivity. Especially, when pulse off-time reaches 3000 μs, a high carrier concentration of 2.86 × 1021 cm−3 and a relatively low electrical resistivity about 0.07 Ω·cm are achieved. [ABSTRACT FROM AUTHOR]