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 (T-s) and oxygen ambient (P-O2) by pulsed laser deposition. It is found that with the increase in T-s and P-O2, the 2 theta 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 2 theta 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 T-s and P-O2 for most of the samples; however, the Hall mobility usually attains its maximum at proper T-s and P-O2. 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 T-s and P-O2, which are due to the changes of optical band gap (E-g) and plasma frequency (omega(p)), respectively. Furthermore the evolutions of E-g and omega(p) with T-s and P-O2 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. (c) 2008 American Institute of Physics.