Generation of oxygen interstitials with excess in situ Ga doping in chemical bath deposition process for the growth of p-type ZnO nanowires

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 532.6eV and the relevant cathodoluminescence (CL) peak at 626nm 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.