Zero-phonon structures in the optical spectra of some transition-metal ions in CdSe crystals

D. Buhmann; H.-J. Schulz; M. Thiede

doi:10.1103/PhysRevB.24.6221

Abstract

Zero-phonon structures of the ${Fe}^{2 +}$ $3 d^{6} {}^{5}E (D) \leftrightarrow {}^{5}T_{2} (D)$ transition in absorption and emission include a coinciding line at 2376 ${cm}^{- 1}$ . Polarized transmission spectra of the ${Co}^{2 +}$ $3 d^{7}$ transition ${}^{4}A_{2} (F) \to {}^{4}T_{1} (P)$ display components split by second-order spin-orbit coupling and indicate an autoionization effect at the 14 175- ${cm}^{- 1}$ line. Symmetry arguments support the interpretation of this antiresonance by a ${Co}^{2 +} \to {Co}^{3 +}$ charge-transfer process with a threshold at about 13 800 ${cm}^{- 1}$ . The ${}^{4}T_{2} (F) \to {}^{4}A_{2} (F)$ luminescence transition of ${Co}^{2 +}$ gives rise to a zero-phonon line at 2867 ${cm}^{- 1}$ . The fine structure of the ${}^{3}T_{1} (F) \to {}^{3}T_{1} (P)$ absorption of ${Ni}^{2 +}$ $3 d^{8}$ suggests a strong reduction of spin-orbit coupling by the Jahn-Teller interaction. With ${Ni}^{2 +}$ ions, radiative recombination from the ${}^{3}T_{1} (P)$ , ${}^{3}A_{2} (F)$ , and ${}^{3}T_{2} (F)$ levels to the ${}^{3}T_{1}$ ground state is detected, and the first and the last transitions exhibit zero-phonon lines at 10 926 and 3607 ${cm}^{- 1}$ , respectively. An abundant novel emission band characterized by a zero-phonon transition at 10 170 ${cm}^{- 1}$ may be related to an $M$ center, i.e., a ${(V_{Se}^{-} V_{Se}^{-})}^{2 +}$ associated defect.

Received 1 December 1980

DOI:https://doi.org/10.1103/PhysRevB.24.6221

Physical Review B

covering condensed matter and materials physics