Abstract
Off-axis electron holography has been used to map the electric potential derived from the spontaneous polarity in a ZnO film. A wedge-shaped ZnO film, in which the holograms and the object wave were reconstructed, was used. To interpret the phase image correctly, the reconstructed amplitude image was used to obtain information on the thickness, which was then applied to eliminate the thickness effect on the phase shift. The electric potential distribution was characterized and the polarity of the ZnO film determined.
Acknowledgments
We acknowledge Professor Xue and Professor Du of the State Key Laboratory of Surface Physics for supplying the sample. This work is supported by the Ministry of Science and Technology (2002CB613502) of China.