Journal of Materials Research

Articles

Electron transport in semiconducting SnO2: Intentional bulk donors and acceptors, the interface, and the surface

Oliver Bierwagena1 c1, Takahiro Nagataa2, Mark E. Whitea3, Min-Ying Tsaia4 and James S. Specka5

a1 Paul-Drude-Institut für Festkörperelektronik, D-10117 Berlin, Germany; and Materials Department, University of California, Santa Barbara, California 93106

a2 National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan; and Materials Department, University of California, Santa Barbara, California 93106

a3 Materials Department, University of California, Santa Barbara, California 93106

a4 Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106

a5 Materials Department, University of California, Santa Barbara, California 93106

Abstract

The transport properties of doped and undoped, high quality, plasma-assisted molecular beam epitaxy grown tin dioxide (SnO2) thin films are reviewed. Intentional doping can vary the SnO2 resistivity over more than seven orders of magnitude from a transparent conducting oxide-like conductivity up to the semi-insulating range. A region of high unintentional n-type conductivity was identified in the substrate interface region and had to be accounted for. Sb was a well-behaved shallow donor up to the regime of conducting oxides. In and Ga were too deep acceptors to achieve p-type conductivity but were suitable to render SnO2 semi-insulating. While the surface accumulation layer strongly influenced contact properties, its conductance was negligible. The methodology used here for studying the transport can also be applied to other semiconducting oxides.

(Received February 28 2012)

(Accepted May 02 2012)

Correspondence:

c1 Address all correspondence to this author. e-mail: bierwagen@pdi-berlin.de

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