Sputtered Al–N codoped p-type transparent ZnO thin films suitable for optoelectronic devices

Aluminum–nitrogen (Al–N) codoped zinc oxide (ZnO) thin films were grown on glass substrate by radio frequency (RF) reactive magnetron sputtering using aluminum doped zinc oxide (AZO, 2.5 wt% Al2O3) target and N2 as reactive gas. The structural, morphology, optical and electrical properties were also investigated with different flow rate of N2 gas. X-ray diffraction results shows that codoped ZnO thin films have similar wurtzite structure like undoped ZnO film. Al–N thin films have high transparency 78% in visible region as the nitrogen flow rate increases the transparency and band gap decreases. The best p-type codoped sample shows a resistivity and hole concentration of 0.554 Ω cm and 8.3 × 1019 cm−3 at room temperature, respectively. Current–voltage (I–V) characteristics of p-type codoped ZnO thin films are also discussed.