Electronic defects in In 2 O 3 and In 2 O 3 :Mg thin films on r ‐plane sapphire

The electrical and structural properties of undoped and Mg‐doped pulsed‐laser‐deposited In 2 O 3 thin films grown on r ‐plane sapphire were investigated by means of Hall‐effect, X‐ray diffraction, and space‐charge spectroscopic methods, such as thermal admittance spectroscopy and deep‐level transient spectroscopy. Undoped thin films are preferentially ( 110 ) ‐oriented but X‐ray diffraction also revealed ( 111 ) ‐orientation. The incorporation of Mg promotes growth along the [ 110 ] direction. Further, the free electron concentration is reduced from 4 × 10 19cm − 3to values below 10 13cm − 3due to incorporation of 1 wt % MgO. We found that a deep‐level defect with a thermal activation energy of 91me V and an apparent capture cross‐section of 4.6 × 10 − 18cm 2 is exclusively incorporated in Mg‐doped thin films.