抄録
Transparent insulating oxide 12CaO·7Al2O3 (C12A7) is converted into electronic conductor by replacing the oxygen ions in the crystallographic cages with electrons. At the low electron concentration (Ne) <-1020 cm-3, C12A7 exhibits semiconductive properties due to hopping of localized electron. With increase of Ne, it becomes metallic state at a critical Ne-1×1021 cm-3. Fully oxygen-replaced C12A7 (C12A7: e-) may be regarded as a room-temperature-stable electride in which electrons serve as anions. Small work function of 2.4 eV comparable to that in metal potassium is a characteristic of C 12A7: e- and makes it a promising candidate for electron emitting source.
