Nitrogen K-edge EXAFS measurements on Mg- and Si-doped GaN

Prior to the analysis, the EXAFS spectra were normalised to the flux of the monochromator by division with the electron yield spectrum from a clean Si wafer. The normalised EXAFS spectra were subjected to subtraction of the a tomic absorption using the AUTOBK program (Mustre de Leon et al., 1991). Th e spectra were corrected for self-absorption effects in the k space using t he procedure described previously (Katsikini et al., 1997). A model for hex agonal GaN (a=3.18 Angstrom, c=5.168 Angstrom) was constructed using the FE FF6 code (Mustre de Leon et al., 1991). The initial values for the Debye-Wa ller (BW) factors were calculated using the correlated Debye model (Sevilla no et al., 1979) and a Debye temperature of 600K.