Vanadium interactions in crystalline silicon

The properties of interstitial vanadium (V-i) in Si and its interactions with the vacancy and the self-interstitial, as well as with hydrogen, are calculated using first-principles techniques. The stable configurations, gap levels, and binding energies agree well with the available experimental data. The nudged-elastic-band method is used to calculate the activation energies for diffusion of V-i in various charge states. They range from 1.46 (for V-i(+)) to 2.04 eV (for V-i(-)). The (trigonal) {V-i, H} pair has a binding energy of 1.15 eV, a donor level at E-c - 0.61 eV, and possibly an acceptor level E-c-0.07 eV. Substitutional vanadium (V-s) can also trap H interstitials and form electrically active {V-s, H} and {V-s, H, H} complexes.