Luminescence of native defects in Zn2GeO4

Pure phase Zn2GeO4 was fabricated by solid state reactions and the products were annealed in various atmospheres, such as O-2, air, N-2, vacuum, Zn, and Ge. The material was a native defect phosphor presenting white-bluish emission and its photoluminescence was about 40% brighter than that of the commercial ZnO phosphor. The electron paramagnetic resonance (EPR) measurements showed the existence of Zn-i(center dot) (or Zn+), an abnormal valence for Zn. Additionally, V-O(center dot), V-Zn('), and ionized V-Ge were also detected by EPR. The model for the luminescent emission of this native defect phosphor was proposed, which may arise from the recombination between the donors (V-O(center dot) and Zn-i(center dot)) and the acceptors (V-Zn(') and ionized V-Ge). (c) 2007 The Electrochemical Study.