In situ observation of substitutional and interstitial Fe atoms in Si after GeV-implantation: An in-beam Mössbauer study

Mössbauer parameters of Fe-related defects in group-IV semiconductors: First principles calculations

“…42 Extensive measurements in n-and p-type samples, where 57 Fe was introduced by several methods, were also carried out by Yoshida and his group. 13,26,43 Although their data for p-type Si seems to be in line with other reported data (δ = 0.8 mm/s), for n-type material a resonance at δ = 0.40 mm/s has been assigned to Fe 0 i . Since our calculations conflict with this assignment, we investigated several possible sources of error, including (i) increasing the BZ sampling grid to MP-4 3 , (ii) bringing the 3s state of Fe into the valence to be treated within the Kohn-Sham scheme, (iii) including an on-site correction to the exchange-correlation energy by means of the GGA+U +J approach as proposed by Liechtenstein et al 113 (with Hubbard and Hund parameters in the range U = 2-5 eV and J = 0-1 eV), and (iv) using the local density approximation to the electronic exchange-correlation interactions.…”

Observation of iron impurity diffusion in silicon under bending stress by Mössbauer spectroscopy

“…Their isomer shifts do not change at all within experimental errors during all measurements. The isomer shifts of the singlet 1, 2 and 3 are −0.12 (3) mm/s, 0.33 (3) mm/s, 0.67 (8) mm/s, respectively, which are in good agreement with those of substitutional Fe s , interstitial Fe 0 i and Fe + i [4][5][6][7]. The third component of Fe + i appears to be too small to discuss precisely in the present experiment, although this component could be more clearly detected before in a simple absorber experiment on the same type of sample.…”

“…We have developed a set-up for 57 Fe Mössbauer spectroscopy combined with an Instron-type tensile testing machine. Mössbauer spectroscopy appears to be an ideal tool to identify lattice sites and charge states of 57 Fe in Si [3][4][5][6], and also to determine the Fe diffusivity through a line broadening if the jump frequency stays within a range between 10 6 and 10 8 jumps/s. In the present paper, we report on an in-situ Mössbauer absorber experiment of a 57 Fe doped n-type Si wafer, on which external bending stress was applied at room temperature.…”

57Fe charge states in MC-Si solar cells under light illumination after GeV-implantation of 57Mn

“…Iron impurities in Si have been intensively investigated for more than 50 years by different experimental techniques [1] including 57 Fe Mössbauer spectroscopy [2][3][4][5][6][7][8][9], because Fe impurities can be easily incorporated into the Si matrix during the processes, and even an extremely low Fe concentration of 10 11 /cm 3 can degrade seriously the electronic properties of silicon-based devices and solar cells. This is due to the deep levels formed in the Si band gap, producing strong trapping centres for the carriers in the devices.…”

“…Interstitial Fe i is well known to form an acceptor level at 0.39 eV from the valence band edge, while substitutional Fe s is expected to form a donor level of 0.69 eV from the first principle calculation [10]. Although interstitial and substitutional Fe appeared as spectral components in 57 Fe Mössbauer experiments [2][3][4][5][6][7][8][9], the charge states could not be identified in terms of different isomer shifts of Mössbauer spectrum experimentally in comparison with the values calculated theoretically.…”