Positron Annihilation Lifetime Studies of Nb ‐Doped TiO ₂ , Sn O ₂ , and Zr O ₂

Abstract

Positron annihilation lifetime spectroscopy ( PALS ) has indicated that Nb 2 O 5 ‐doped TiO 2 samples treated in either Ar or air at 1400°C for 48 h are both charge‐compensated by Ti vacancies, but with statistically significant differences between the results. A Ta 2 O 5 ‐doped air‐sintered TiO 2 sample also showed behavior similar to the Nb 2 O 5 ‐doped air‐sintered TiO 2 . In addition, Nb 2 O 5 ‐doped SnO 2 samples sintered in air at 1400°C for 1 h showed evidence of Sn vacancy cluster formation, with no indications of Sn 2+ compensation from ultraviolet irradiation studies. PALS studies of air‐sintered ZrO 2 did not show any evidence of Zr vacancies after doping with Nb 2 O 5 .