Surface origin of high conductivities in undoped In 2O 3 thin films

S. Lany, A. Zakutayev, T. O. Mason, J. F. Wager, K. R. Poeppelmeier, J. D. Perkins, J. J. Berry, D. S. Ginley, A. Zunger

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Abstract

The microscopic cause of conductivity in transparent conducting oxides like ZnO, In 2O 3, and SnO 2 is generally considered to be a point defect mechanism in the bulk, involving intrinsic lattice defects, extrinsic dopants, or unintentional impurities like hydrogen. We confirm here that the defect theory for O-vacancies can quantitatively account for the rather moderate conductivity and off-stoichiometry observed in bulk In 2O 3 samples under high-temperature equilibrium conditions. However, nominally undoped thin-films of In 2O 3 can exhibit surprisingly high conductivities exceeding by 4-5 orders of magnitude that of bulk samples under identical conditions (temperature and O 2 partial pressure). Employing surface calculations and thickness-dependent Hall measurements, we demonstrate that surface donors rather than bulk defects dominate the conductivity of In 2O 3 thin films.

Original languageEnglish
Article number016802
JournalPhysical Review Letters
Volume108
Issue number1
DOIs
Publication statusPublished - Jan 5 2012

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ASJC Scopus subject areas

  • Physics and Astronomy(all)

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