Electrical Conductivity of Polycrystalline A1 2 O 3 Doped with Silicon

Direct current conductivity was measured for polycrystalline Alz03 doped with silicon, which is found to act as a single donor, the donor level lying ∼165 kJ/mol (∼1.7 eV) below the conduction band. Silicon in excess of the solubility limit (∼220 ppm at 1500°C, 300 ppm at 1600°C) is present as a glassy aluminosilicate second phase. Silicon dissolved in Al 2 O 3 tends to segregate at grain boundaries.