Abstract
Tin-doped indium oxide (ITO) ceramics prepared by a high-temperature solid-state synthetic procedure have been studied over the composition range 1-6 at.% Sn by X-ray and ultraviolet photoelectron spectroscopy (XPS and UPS) and high-resolution electron energy loss spectroscopy (HREELS). Surface tin enrichment is evident from XPS with a heat of segregation of around -40 kJ mole-1. However, the surface free-carrier concentration probed via the conduction-to-valence band intensity ratio in UPS or the surface plasmon frequency in HREELS is lower than the nominal tin concentration. It is concluded that electrons associated with segregated Sn ions in the topmost surface plane occupy a lone-pair-likesp hybrid surface state, while the region immediately below the surface is depleted in free carriers as a result of donor trapping effects and evaporation of tin during preparation. © 1987 Academic Press, Inc. All rights reserved.
| Original language | English |
|---|---|
| Pages (from-to) | 340-350 |
| Number of pages | 10 |
| Journal | Journal of Solid State Chemistry |
| Volume | 68 |
| Issue number | 2 |
| Publication status | Published - Jun 1987 |