Advancing Al-doped ZnO thin films structural, optical and electrical properties of low temperature PET substrates via flash lamp annealing

Abstract In this study, aluminum-doped zinc oxide (AZO) thin films were deposited onto a low-temperature polyethylene terephthalate (PET) substrate using DC magnetron sputtering. Deposition parameters included power range of 100−300 W, a working pressure of 15 mTorr, and a substrate temperature of 50 °C. Post-deposition, flash lamp annealing (FLA) was employed as a rapid thermal processing method with a pulse duration of 1.7 ms and energy density of 7 J·cm −2 , aimed at enhancing the film's quality while preserving the temperature-sensitive PET substrate. FLA offers advantages over conventional annealing, including shorter processing times and improved material properties. The structural, optical, and electrical characteristics of the AZO films were assessed using X-ray diffraction, field emission scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, ultraviolet−visible spectroscopy, and Hall effect measurements. The results demonstrated that properties of AZO films varied with deposition and annealing conditions. Films deposited at 200 W and subjected to FLA exhibited superior crystallinity, with average visible light transmittance exceeding 80% and resistivity as low as 0.38 Ω·cm representing 95% improvement in transmittance. Electrical analysis revealed that carrier concentration, mobility, and resistivity were influenced by both sputtering and annealing parameters. These findings underscore the effectiveness of FLA in optimizing AZO thin film properties, highlighting potential in optoelectronics applications.