Journal of Materials Research

Rapid Communications

Positive Hall coefficients obtained from contact misplacement on evident n-type ZnO films and crystals

Takeshi Ohgakia1 c1, Naoki Ohashia1, Shigeaki Sugimuraa1 p1, Haruki Ryokena1, Isao Sakaguchia1, Yutaka Adachia1 and Hajime Hanedaa1

a1 National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan

Abstract

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)

Key Words:

  • Electrical properties;
  • Hall effect;
  • Semiconducting

Correspondence:

c1 Address all correspondence to this author. e-mail: OGAKI.Takeshi@nims.go.jp

p1 Present address: Tokyo Denpa Co. Ltd. (TEW), 5-6-11 Chuo, Ohta-ku, Tokyo 143-0024, Japan

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