Experimental Hall electron mobility of bulk single crystals of transparent semiconducting oxides
Zbigniew Galazka, K. Irmscher, Mike Pietsch, Steffen Ganschow, D. Schulz, Detlef Klimm, I. Hanke, Thomas Schroeder, Matthias Bickermann
Abstract
Abstract We provide a comparative study of basic electrical properties of bulk single crystals of transparent semiconducting oxides (TSOs) obtained directly from the melt (9 compounds) and from the gas phase (1 compound), including binary (β-Ga 2 O 3 , In 2 O 3 , ZnO, SnO 2 ), ternary (ZnSnO 3 , BaSnO 3 , MgGa 2 O 4 , ZnGa 2 O 4 ), and quaternary (Zn 1−x Mg x Ga 2 O 4 , InGaZnO 4 ) systems. Experimental outcome, covering over 200 samples measured at room temperature, revealed n-type conductivity of all TSOs with free electron concentrations ( n e ) between 5 × 10 15 and 5 × 10 20 cm −3 and Hall electron mobilities ( μ H ) up to 240 cm 2 V −1 s −1 . The widest range of n e values was achieved for β-Ga 2 O 3 and In 2 O 3 . The most electrically conducting bulk crystals are InGaZnO 4 and ZnSnO 3 with n e > 10 20 cm −3 and μ H > 100 cm 2 V −1 s −1 . The highest μ H values > 200 cm 2 V −1 s −1 were measured for SnO 2 , followed by BaSnO 3 and In 2 O 3 single crystals. In 2 O 3 , ZnO, ZnSnO 3 , and InGaZnO 4 crystals were always conducting, while others could be turned into electrical insulators. Graphic abstract