The effect of charge and spin state on the Infrared spectra and hyperfine coupling constants of point defects in Silicon

The effect of the charge of a point defect on the infrared spectrum and the hyperfine coupling constants is discussed with reference to the VO defect in silicon. Five charge states have been considered, from +2e to -2e. Calculations are performed by using a local Gaussian type basis set and the B3LYP hybrid functional. The dominant peak in the IR spectrum increases linearly from 708 cm(-1) (+2 charge), to 904 cm(-1) (-2 charge). The intensity decreases from 4073 to 1727 km/mol, as a consequence of the reduced polarity of the Si-O bond. Also the hyperfine constants differ by large percentages along the series. Although limited to a single defect, the present study shows that both the IR and EPR techniques are able to discriminate the charge state of the defect, also in the cases in which more than one charge state is present in the same sample.

Automated summary

This study discusses the impact of the charge of a point defect on the infrared spectrum and hyperfine coupling constants, using the VO defect in silicon as a reference. The calculations show that the charge state of the defect significantly affects the dominant peak position and intensity in the infrared spectrum, as well as the hyperfine constants.