Thesis presented December 07, 2006

Abstract:
Electronic properties of the diluted magnetic semiconductor (Ga,Mn)N were studied by x-ray absorption spectroscopy at the K-edge of Mn. The measured x-ray absorption spectra were further interpreted using the ab initio calculations. Two pre-edge absorption lines are observed in the x-ray absorption spectra: the first line was attributed to electronic transitions into 3d states of Mn of spin up, while the second line corresponds to transitions into 3d states of Mn of spin down. This interpretation allows us to determine the valence state of Mn: two absorption lines are present in the pre-edge structure of Mn³⁺ and only one line remains in case of Mn²⁺. Such a change of the pre-edge structure was checked experimentally on (Zn,Mn²⁺)Te and on (Ga,Mn²⁺)As. In addition, the distribution of Mn in (Ga,Mn)N can be studied using the interpretation: the shape of the spectra points to a homogeneous distribution of Mn in our (Ga,Mn)N samples.

Keywords:
diluted magnetic semiconductor, GaN:Mn, GaAs:Mn, Ge:Mn, XANES, x-ray absorption spectroscopy, ab initio, valence

On-line thesis.