Electron capture into the two-electron O- state in GaP

A reinterpretation of the ir spectra of Dean and Henry in oxygen-doped GaP strongly suggests that they involve radiative capture and excitation of the second electron bound to oxygen. Further, this electron is localized near the nearest-neighbor Ga ions, it is bound by ∼0.9 eV as found also by Samuelson and Monemar, and its electron-phonon coupling is small-λ0.6, ω47.5 meV-in disagreement with Henry et al. The analysis emphasizes the usefulness of the "phonon signature" in identifying deep levels from their optical spectra. © 1978 The American Physical Society.