Synthesis and characterization of NiO-doped p-type AZO films fabricated by sol–gel method

NiO-doped p-type AZO (Al/Zn=1.5at.%) films were synthesized on glass substrates using a simple and low cost sol–gel solution method. p-type conductivity could be achieved by annealing the NiO:AZO films in N₂/H₂ forming gas at 550°C. The real Al/Zn and Ni/Zn ratio, hole concentration, hole mobility and resistivity of the 1.5–2mol% NiO-doped AZO films were 0.26–0.29, 0.06–0.09, 3.15×10¹⁸–2.18×10²⁰cm⁻³, 2.33–12.76cm²/Vs, and 2.39×10⁻¹–1.24×10⁻²Ωcm, respectively. I–V measurements of the p–n junction (ITO/NiO:AZO) revealed rectifying I–V characteristics, confirming that these NiO:AZO films exhibit p-type conductivity. This study opens the possibility of developing highly conductive p-type composite transparent conducting oxides for optoelectronic devices.