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The Effects of Magnetic Field Size on the Electronic Structure of Al ‐Doped ZnO Thin Films Studied by X ‐ray Absorption and Emission Spectroscopy
Author(s) -
Chiou JauWern,
Huang WeiHao,
Sun ShihJye,
Yu ChangFeng,
Chou Hsiung,
Yang HungDuen,
Yu YuehChung,
Chan TingShan,
Lin HongJi,
Kumar Krishna,
Yang Wanli,
Guo Jinghua
Publication year - 2014
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.12689
Subject(s) - xanes , thin film , materials science , analytical chemistry (journal) , band gap , absorption spectroscopy , crystallite , absorption edge , condensed matter physics , spectroscopy , chemistry , optics , nanotechnology , optoelectronics , physics , chromatography , quantum mechanics , metallurgy
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.