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Past Events
Electrical Conductivity of Li-Doped ZnO
| Speaker: | Dr. Eun Dong KIM |
| Affiliation: | Senior Advisor, Adv. Mater. Res. Dev., Korea Electrotechnology Research Institute |
| Date: | February 23, 2009 (Mon) |
| Time: | 4:00-5:00 p.m. |
| Venue: | Room 522, 5/F, Chong Yuet Ming Physics Building, HKU |
Abstract:
Solid solution models of ZnO with Li2O were proposed in relation to its nonstoichiometry and thermal disorder reactions. From their mass-action relations, behaviors of Li ions in ZnO lattice were predicted. Considering the Frenkel disorder reaction of substituted lithium, LiZn = Li i + VZn, we can conclude:
(1) At lower oxygen partial pressures, Li ions preferentially occupy the interstitial sites an d the concentration of the resulted Lii is inversely proportional to PO21/4. ZnO doped with Li at l ower oxygen partial pressures always shows n-type conductivity because the concentration of d onors inversely proportional to PO2 is higher than that of acceptors proportional to PO2 .
(2) At higher oxygen partial pressures, the dissolved Li ions in ZnO preferentially substit ute the normal Zn lattice sites and the concentration of the resulted Li Zn is proportional to PO21/4. Because LiZn is known as an acceptor, ZnO can have the p-type conductivity by Li-doping at hi gher oxygen partial pressures.
Coffee and tea will be served 20 minutes prior to the seminar.