Defect Chemistry and Electrical Properties of Thallium Oxide Single Crystals

Ehdectrical resistivity and Hall voltage were measured between 4.2 and 300 K on T1 2 O 3 crystals annealehd at 550°C for 24 h under oxygen pressures of 2×10 4 to 10 7 Pa. The carrier concentration varied from 7.97×10 20 to 5.08×10 20 cm −3 , the low‐temperature Hall mobility from 131 to 189 cm 2 /V.s, and the Fermi level from 7.1×10 4 to 5.05×10 4 J/mol above the bottom of the conduction band as P 02 was increased from 2×10 4 to 10 7 Pa. The dependence of Fermi level on carrier concentration and P 0l was consistent with a parabolic density‐of‐states function describing the conduction band. Over the entire region of oxygen pressure investigated, Fermi‐Dirac statistics were required to describe the dependence of carrier concentration on P 02 .