Comprehensive investigation of structural, electrical, and optical properties for ZnO:Al films deposited at different substrate temperature and oxygen ambient

c -axis oriented polycrystalline ZnO:Al (AZO) films were deposited at different substrate temperature (Ts) and oxygen ambient (PO2) by pulsed laser deposition. It is found that with the increase in Ts and PO2, the 2θ position of AZO (0002) shifts to higher angle, which can be attributed to the different amounts and species of defects in AZO films. Furthermore, the full width at half maximum of 2θ and (0002) rocking curve indicate the different crystalline qualities for AZO films grown at different conditions. At the same time, the carrier concentration decreases with the increase in Ts and PO2 for most of the samples; however, the Hall mobility usually attains its maximum at proper Ts and PO2. Moreover the transport of electrons may be governed by different mechanisms for AZO films grown at different conditions. The AZO transmission spectra show that the ultraviolet absorption edge and infrared transparency limit shift toward longer wavelength with the increase in Ts and PO2, which are due to the changes of optical band gap (Eg) and plasma frequency (ωp), respectively. Furthermore the evolutions of Eg and ωp with Ts and PO2 are consistent with that of electrical properties. The intensity of photoluminescence is found to correlate with the carrier concentration which indicates that the transition of electrons between conduction and valence bands dominates the room temperature emission of AZO films.