The Effects of Magnetic Field Size on the Electronic Structure of Al ‐Doped ZnO Thin Films Studied by X ‐ray Absorption and Emission Spectroscopy

This study examines Al ‐doped ZnO ( AZO ) transparent conductive thin films prepared on glass substrate using the pulsed laser deposition method with an expanding magnetic field perpendicular to the sample surface. O K ‐, Zn L 3 ‐, and Al K ‐edge X ‐ray absorption near‐edge structure ( XANES ) and X‐ray emission spectroscopy ( XES ) were used to investigate the relationship between the effects of magnetic field size and the electronic structure of AZO thin films. Analysis of the XANES spectra showed increasing O 2 p states as film resistance decreases, suggesting that the enrichment of the O 2 p ‐dangling bond along the c ‐axis is the main factor affecting the electric performance of AZO thin films. Magnetic field size affects electrons itinerating from Zn atoms to Al sites through O 2 p –Zn 3 d and O 2 p –Al 3 sp hybridization and consequently weakens O 2 p –Zn 3 d hybridization with the downsizing of the crystallite size. XES and XANES spectra of O 2 p states at the O K ‐edge exhibit that the conduction‐band minimum affects E g and the valence‐band maximum is nearly unaffected by changes in magnetic field size. Factors affecting the resistance/electric conductivity of AZO thin films are the preferential orientation of (002) along the c ‐axis, the thermal/annealing effect accompanied by the changes of magnetic field size, the surface effect, energy bandgap, and the density of unoccupied O 2 p ‐derived states.