Self-trapping of the d-d charge transfer exciton in rock-salt structured Zn1−xNixO evidenced by soft X-ray excited luminescence

摘要: Luminescence spectra of NiO and solid solutions Zn1–xNixO have been investigated under vacuum ultra-violet (VUV) soft X-ray (XUV) excitation (DESY, Hamburg). Photoluminescence (PL) show broad emission violet green bands centered at about 3.2 2.6 eV, respectively. The PL (PLE) spec-tral evolution lifetime measurements reveal that the two mechanisms with short long decay times, at-tributed to d(eg)-d(eg) p(π)-d charge transfer (CT) transitions in range 4–6 respectively, are responsible for observed emissions. XUV makes it possible avoid predominant role surface effects luminescence a bulk puzzling well isolated doublet very narrow lines. These lines close energies near 3.3 eV attributed recombination self-trapped d-d CT excitons formed by coupled Jahn-Teller Ni+ Ni3+ centers. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)