Preparation of Na delta-doped p-type ZnO thin films by pulsed laser deposition using NaF and ZnO ceramic targets

• Oxygen pressure together with substrate temperature determines conductivity of films.
• The Na δ-doped ZnO films show good p-type conduction.
• Na incorporated in the film exists as NaZn, which acts as acceptor.
• A method to realize p-type ZnO thin films doping with Na is developed.

Na δ-doped p-type ZnO thin films were fabricated on quartz substrates with the structure of ZnO/Na (δ-layer) multi-layers by pulsed laser deposition. NaF ceramic target was used as Na source. The effects of oxygen pressure and substrate temperature on the electrical properties of Na δ-doped ZnO thin films are discussed. An optimized result with a resistivity of 29.8 Ω · cm, Hall mobility of 0.263 cm2/V · s, and hole concentration of 7.9 × 1017 cm− 3 is achieved, and electrically stable over several months. The present work is of interest for developing a method to realize p-type ZnO thin films doping with Na.