Hopping versus bulk conductivity in transparent oxides: 12CaO·7Al2O3
نویسندگان
چکیده
First-principles calculations of the mayenite-based oxide, fCa12Al14O32gs2ed, reveal the mechanism responsible for its high conductivity. A detailed comparison of the electronic and optical properties of this material with those of the recently discovered transparent conducting oxide, H-doped UV-activated Ca12Al14O33, allowed us to conclude that the enhanced conductivity in fCa12Al14O32gs2ed is achieved by elimination of the Coulomb blockade of the charge carriers. This results in a transition from variable range-hopping behavior with a Coulomb gap in H-doped UV-irradiated Ca12Al14O33, to bulk conductivity in fCa12Al14O32gs2ed. Further, the high degree of delocalization of the conduction electrons obtained in fCa12Al14O32gs2ed indicates that it cannot be classified as an electride, as originally suggested. © 2004 American Institute of Physics. [DOI: 10.1063/1.1781362]
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