Electron Capture into the Two-ElectronO−State in GaP

Abstract

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—$\lambda \approx 0.6$, $\hslash \omega \approx 47.5$ meV—in disagreement with Henry et al. The analysis emphasizes the usefulness of the "phonon signature" in identifying deep levels from their optical spectra.