Surface Origin of High Conductivities in Undoped In2O3 Thin Films
The microscopic cause of conductivity in transparent conducting oxides like ZnO, In{sub 2}O{sub 3}, and SnO{sub 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{sub 2}O{sub 3} samples under high-temperature equilibrium conditions. However, nominally undoped thin-films of In{sub 2}O{sub 3} can exhibit surprisingly high conductivities exceeding by 4-5 orders of magnitude that of bulk samples under identical conditions (temperature and O{sub 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{sub 2}O{sub 3} thin films.
- Research Organization:
- National Renewable Energy Laboratory (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE Office of Science, Basic Energy Sciences; Energy Frontier Research Center for Inverse Design
- DOE Contract Number:
- AC36-08GO28308
- OSTI ID:
- 1039476
- Report Number(s):
- NREL/JA-5900-53468
- Journal Information:
- Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 1 Vol. 108; ISSN 0031-9007; ISSN PRLTAO
- Country of Publication:
- United States
- Language:
- English
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