Resonant boron acceptor states in semiconducting diamond

High-excited discrete states of boron hydrogenlike acceptors in crystalline diamond have been measured by temperature-dependent infrared absorption spectroscopy. We distinguish the boron resonant states in diamond crystals from the localized boron states in the band gap by differentiating the impurity transitions within state continua of the valence light- and heavy-hole subbands on the basis of their relative oscillator strengths, specific selection rules, and temperature dependences. Constraints on the boron binding energy and spin-orbit splitting of the valence band have been derived by analysis of the structure of the infrared absorption spectra of boron-doped diamond, in particular by a comparison with boron spectra in other semiconductors with a diamond lattice.