p-d charge transfer excitons in Zn1-xNixO under inner shell excitation

The paper presents results of the study of two narrow luminescence lines I1 and I2 at the energies of 3.339 and 3.393 eV respectively in solid state solutions Zn1‐xNixO. The luminescence spectroscopy with a sub‐nanosecond time resolution upon selective photoexcitation in the energy range of the inner shell Zn M‐edge absorption was used to promote the earlier proposed mechanism of the I1 and I2 lines origin. Photoluminescence spectra of solid state solutions Zn1‐xNixO at fast and slow time windows under soft X‐ray excitation are discussed. The doublet of I1 and I2 lines is believed to arise due to the radiative annihilation of p‐d excitons. Different possible mechanisms of emergence of two narrow luminescence lines I1 and I2 in solid state solutions Zn1‐xNixO are considered. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)