a1 National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
We report on the effect of sample non-uniformity on the results of Hall-effect measurements. False positive Hall coefficients were obtained from an evidently n-type ZnO single crystal, although four electrodes with low contact resistance were made and the Van der Pauw parameter for this electrode configuration was close to 1.00. Further position-sensitive characterization revealed that the false positive Hall coefficient was due to non-uniform electrical properties of the sample. To demonstrate a false positive sign of the Hall coefficient due to sample non-uniformity, we devised a model structure made from evident n-type ZnO thin film and successfully reproduced a false positive Hall coefficient from n-type ZnO.
(Received April 4 2008)
(Accepted June 12 2008)
p1 Present address: Tokyo Denpa Co. Ltd. (TEW), 5-6-11 Chuo, Ohta-ku, Tokyo 143-0024, Japan