Calculation of formation energy of oxygen vacancy in ZnO based on photoluminescence measurements.
The formation energy of an oxygen vacancy in ZnO was calculated. The photoluminescence intensity of green emission was used as a measure of vacancy concentration, and its variation as a function of reduction temperature was monitored. This enabled a thermodynamic approach based on experimental data, which is in contrast with most previous studies, which focused on a theoretical treatment based on first principles methods. Two reduction conditions were used: hydrogen gas flow and a CO/CO(2) atmosphere generated using activated carbon. The two cases were compared, and mechanisms for the formation of oxygen vacancies during thermal treatment were investigated. The similar results obtained for the two cases indicate that the proposed models of V(O) formation are reasonable.
Kim
Yongseon
Y
Department of Materials Science and Engineering, Seoul National University, Seoul 151-742, Korea.
Kang
Shinhoo
S