Thermal annealing using ultra-short laser pulses to improve the electrical properties of Al:ZnO thin films

Abstract Industrial-grade Al:ZnO thin films, were annealed by UV picosecond laser irradiation in argon atmosphere. A remarkable increase of both the carrier density and electron mobility was measured, while the optical properties in the 400-1000 nm range did not change significantly. We studied the microstructure of the films, in order to explain the observed macroscopical changes upon ultra-short pulsed laser annealing. The effects of the ps-laser irradiation are shown to be attributed to the formation of defects and a local atomic rearrangement on the sub-nm scale. This interpretation is rigorously based on the cross-referenced analysis of different experimental techniques (i.e. SEM, AFM, positron annihilation, optical spectroscopy, Hall measurements, Raman spectroscopy, XPS and XRD). The results of this study can be used to develop a new, viable, technological processing technique to further improve Al:ZnO electrodes. © 2015 Acta Materialia Inc.

Al:ZnO; Annealing; Electrical properties; Laser-induced defects; Ultrafast laser Aluminum; Annealing; Argon lasers; Defects; Electric properties; Irradiation; Metallic films; Optical films; Optical properties; Thin films; Ultrafast lasers; Ultrashort pulses; Zinc oxide; Atomic rearrangements; Experimental techniques; Laser-induced defect; Macroscopical changes; Optical spectroscopy; Picosecond laser irradiation; Processing technique; ZnO; Pulsed lasers

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