Indium tin oxide (ITO) and Er3+-doped ITO powders were prepared by a conventional ceramic method. The density of ITO powders and optical absorption spectra of Er3+ ions in Er3+-doped ITO were measured as a function of the SnO2 doping level. The results obtained were discussed in terms of the trapping center for immobile electrons in ITO. Observed densities of ITO powders were in good agreement with those calculated from their lattice parameters, assuming that the immobile electrons were trapped at the excess interstitial oxygen. The optical absorption spectra of Er3+-doped ITO indicated that some In3+ ions in ITO were surrounded by 7 and/or 8 oxygen ions; the increase in the coordination number of In3+ from 6 in In2O3 to 7 and/or 8 in ITO must be caused by the introduction of excess interstitial oxygen into the quasi-anion site in the C-type rare-earth lattice upon SnO2 doping. It was concluded that the immobile electrons in ITO are trapped at the excess interstitial oxygen, and that the mechanism of conduction carrier generation and compensation upon SnO2 doping int In2O3 can be expressed by the defect equation, 2SnO2→2SnIn·+2(1-z)e′+zO″i +3OOx+(1-z)/2O2.
|Number of pages||6|
|Journal||Applied Physics A: Materials Science and Processing|
|Publication status||Published - 2000 Dec|
ASJC Scopus subject areas
- Materials Science(all)