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Title: Quantification and impact of nonparabolicity of the conduction band of indium tin oxide on its plasmonic properties

Doped indium tin oxide (ITO) behaves as a Drude metal with a plasma frequency that is controlled by its free carrier density. In this work, we systematically tune this frequency across the mid-infrared range by annealing treatments in a reducing environment that produce high electron concentrations (∼10{sup 21 }cm{sup −3}). The changes in ITO's optical properties that result from the changes in carrier density are measured by attenuated total reflection measurements. These optical frequency measurements are complemented by Hall measurements to obtain a comprehensive picture of the Drude response of the ITO films. It was found that a complete description of the optical properties at very high carrier densities needs to account for the nonparabolicity of the conduction band of ITO and a reduced carrier mobility. More specifically, an increase in carrier concentration from 6.2 × 10{sup 19 }cm{sup −3} to 1.4 × 10{sup 21 }cm{sup −3} comes with a change of the effective electron mass from 0.35 m{sub 0} to 0.53 m{sub 0} and a decrease in the optical frequency mobility from about 20 cm{sup 2} V{sup −1} s{sup −1} to 9 cm{sup 2} V{sup −1} s{sup −1}.
Authors:
; ; ; ; ; ;  [1]
  1. Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305 (United States)
Publication Date:
OSTI Identifier:
22391894
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 18; 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; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANNEALING; CARRIER DENSITY; CARRIER MOBILITY; DOPED MATERIALS; ELECTRONIC STRUCTURE; ELECTRONS; INDIUM; LANGMUIR FREQUENCY; OPTICAL PROPERTIES; TIN OXIDES