Positron Annihilation-Induced Auger Electron Spectroscopy Measurements of a TiO₂(110) Surface

Abstract

We report here positron annihilation-induced Auger electron spectroscopy measurements of an as received TiO2(110) surface. We observe peaks at ∼ 250 eV and ∼ 500 eV due to the Auger decay of annihilation-induced 1s holes in carbon (C KVV), and oxygen (O KVV) respectively. In addition to these KVV Auger peaks we observe a broad, low energy peak extending up to 15 eV. Since the incident positron beam energy of 1.5 eV is well below the energy threshold required to directly knock out electrons with kinetic energies up to 15 eV, this peak must be Auger-related. Based on energy conservation requirements and its considerable spectral weight, we argue that this low energy peak is principally due to the Auger decay of both annihilation induced 2s core holes in oxygen and annihilation induced valence holes in carbon.