Electronic and optical properties of Ga{sub 3−x}In{sub 5+x}Sn{sub 2}O{sub 16}: An experimental and theoretical study
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208 (United States)
- Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208 (United States)
Experimental measurements of optical and electronic properties and local-density approximation (LDA) calculations on polycrystalline Ga{sub 3−x}In{sub 5+x}Sn{sub 2}O{sub 16}—the so-called “T-phase” in the Ga{sub 2}O{sub 3}-In{sub 2}O{sub 3}-SnO{sub 2} ternary system—have revealed it to be a good candidate for n-type transparent conducting oxide applications, particularly in the replacement of tin-doped indium oxide as a transparent electrode in organic photovoltaics. Room temperature conductivity of over 1000 S cm{sup −1} was measured in polycrystalline bulk samples. Band structure calculations reveal a highly dispersed conduction band, corresponding to an electron effective mass of about 0.2 m{sub e}. Normalized carrier mobility and concentration trends indicate that conductivity changes in T-phase are attributable to changes in carrier concentration, with mobility remaining relatively constant through the range of processing conditions and sample composition. Screened exchange LDA calculations yield a fundamental band gap of about 2.60 eV. A relatively constant optical band gap in the range of 2.9–3.0 eV along the range of T-phase composition was measured by diffuse reflectance of bulk samples, whereas ab-initio simulations predict a decreasing fundamental band gap with increasing In-to-Ga ratio. This is attributed to an increasing Burstein-Moss shift—corresponding to increasing free electron concentration—with increasing In-to-Ga ratio.
- OSTI ID:
- 22271309
- Journal Information:
- Journal of Applied Physics, Vol. 115, Issue 1; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CARRIER MOBILITY
CHARGE CARRIERS
CONCENTRATION RATIO
EFFECTIVE MASS
ELECTRONIC STRUCTURE
ELECTRONS
GALLIUM OXIDES
INDIUM OXIDES
N-TYPE CONDUCTORS
OPTICAL PROPERTIES
PHOTOVOLTAIC EFFECT
POLYCRYSTALS
TEMPERATURE RANGE 0273-0400 K
TIN OXIDES