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Title: Electronic and optical properties of Ga{sub 3−x}In{sub 5+x}Sn{sub 2}O{sub 16}: An experimental and theoretical study

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.
Authors:
;  [1] ; ;  [2] ;  [3]
  1. Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States)
  2. Department of Chemistry, Northwestern University, Evanston, Illinois 60208 (United States)
  3. Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208 (United States)
Publication Date:
OSTI Identifier:
22271309
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 1; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, 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