The effects of structural relaxation (SR) on the electronic state of oxygen vacancies (VO s) in amorphous oxide semiconductors is investigated. Without redox reactions, the concentration of VO s in the shallow-donor state (NDS) increases about 103 times with increases in the annealing temperature from 300 to 450 °C. The reduction in the free volume size and transformation of VO s in either deep-donor or electron-trap states into the shallow-donor state during SR is the primary mechanism responsible for the increase in NDS.
- Han-Wool Yeon
- Seung-Min Lim
- Young-Chang Joo