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In this study, the effect of annealing atmosphere on the electrical properties, optical properties, microstructure and defects of ZnO∶Al films was investigated in detail. The crystallization, surface and fracture morphologies, electrical properties, resistivity, transmittance, Raman vibration and photoluminescence of ZnO∶Al films were characterized by SEM, XRD, Hall effect test instruments, ultraviolet-visible spectrophotometer, Raman spectra and PL spectra. The results show that after annealing in air atmosphere, the carrier concentration of AZO films decreases from 1.63 × 1020 cm−3 to 7.1 × 1018 cm−3, the optical band gap varies from 3.51 eV to 3.37 eV, the transmittance in NIR increased and the band edge emission in PL spectrum shifted from 3.49 eV to 3.34 eV. On the other hand, while the carrier concentration of AZO films annealing in H2 atmosphere was 5.3 × 1020 cm-3, the optical band gap increases to 3.78 eV, the transmittance in NIR decreases remarkably, the emission intensity of the band edge increases by more than 10 times and the band edge emission in PL spectrum shifts to 3.57 eV. Furthermore, the 4 order LO phonons are observed in ZnO:Al films annealed in air.

Highly transparent indium-free multilayers of TiO2/Cu/TiO2 were obtained by means of annealing. The effects of Cu thickness and annealing temperature on the electrical and optical properties were investigated. The critical thickness of Cu mid-layer with optimal electrical and optical properties was 10 nm, with the figure of merit reaching as high as 5 × 10−3 Ω−1. Partial crystallization of the TiO2 layer enhanced the electrical and optical properties upon annealing. Electrothermal experiments showed that temperatures of more than 100 °C can be reached at a heating rate of 2 °C/s without any damage to the multilayers. The experimental results indicate that reliable transparent TiO2/Cu/TiO2 multilayers can be used for electrothermal application. [ABSTRACT FROM AUTHOR]