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arXiv · 0902.4614

Local structure of (Ga,Fe)N and (Ga,Fe)N:Si investigated by x-ray absorption fine structure spectroscopy

Mauro Rovezzi·Francesco D'Acapito·Andrea Navarro-Quezada·Bogdan Faina·Tian Li·Alberta Bonanni·Francesco Filippone·Aldo Amore Bonapasta·Tomasz Dietl
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Abstract

X-ray absorption fine-structure (XAFS) measurements supported by {\em ab initio} computations within the density functional theory (DFT) are employed to systematically characterize Fe-doped as well as Fe and Si-co-doped films grown by metalorganic vapour phase epitaxy. The analysis of extended-XAFS data shows that depending on the growth conditions, Fe atoms either occupy Ga substitutional sites in GaN or precipitate in the form of $ε$-Fe$_3$N nanocrystals, which are ferromagnetic and metallic according to the DFT results. Precipitation can be hampered by reducing the Fe content, or by increasing the growth rate or by co-doping with Si. The near-edge region of the XAFS spectra provides information on the Fe charge state and shows its partial reduction from Fe$^{+3}$ to Fe$^{+2}$ upon Si co-doping, in agreement with the Fe electronic configurations expected within various implementations of DFT.

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Mauro Rovezzi, Francesco D'Acapito, Andrea Navarro-Quezada, Bogdan Faina, Tian Li, Alberta Bonanni, Francesco Filippone, Aldo Amore Bonapasta, Tomasz Dietl. 2009-03-01. Local structure of (Ga,Fe)N and (Ga,Fe)N:Si investigated by x-ray absorption fine structure spectroscopy. https://doi.org/10.1103/physrevb.79.195209

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