The current work focuses on the incorporation of excess amount of gallium (Ga) in zinc oxide (ZnO) nanowires to generate oxygen interstitials for developing p-type conductivity. Ga has been used as an n-type dopant in ZnO lattice by reducing its inherent vacancies up to 3% molar ratio of Ga and Zn employing chemical bath deposition technique. However, the addition of more than 4% of gallium nitrate in the bath solution creates oxygen interstitials which are confirmed from the presence of X-ray photoelectron spectroscopy (XPS) peak at 532.6 eV and the relevant cathodoluminescence (CL) peak at 626 nm of the grown Ga-doped ZnO nanowires. The p-type conductivity of such ZnO nanowires has been confirmed from current–voltage, capacitance–voltage and Hall voltage measurements. The reproducibility of the results indicates the incorporation of excess Ga to be a promising technique for growing p-type ZnO nanowires. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.