CdO as the archetypical transparent conducting oxide. Systematics of dopant ionic radius and electronic structure effects on charge transport and band structure

Yu Yang, Shu Jin, Julia E. Medvedeva, John R. Ireland, Andrew W. Metz, Jun Ni, Mark C Hersam, Arthur J Freeman, Tobin J Marks

Research output: Contribution to journalArticle

116 Citations (Scopus)

Abstract

A series of yttrium-doped CdO (CYO) thin films have been grown on both amorphous glass and single-crystal MgO(100) substrates at 410 °C by metal-organic chemical vapor deposition (MOCVD), and their phase structure, microstructure, electrical, and optical properties have been investigated. XRD data reveal that all as-deposited CYO thin films are phase-pure and polycrystalline, with features assignable to a cubic CdO-type crystal structure. Epitaxial films grown on single-crystal MgO(100) exhibit biaxial, highly textured microstructures. These as-deposited CYO thin films exhibit excellent optical transparency, with an average transmittance of >80% in the visible range. Y doping widens the optical band gap from 2.86 to 3.27 eV via a Burstein-Moss shift. Room temperature thin film conductivities of 8540 and 17 800 S/cm on glass and MgO(100), respectively, are obtained at an optimum Y doping level of 1.2-1.3%. Finally, electronic band structure calculations are carried out to systematically compare the structural, electronic, and optical properties of the In-, Sc-, and Y-doped CdO systems. Both experimental and theoretical results reveal that dopant ionic radius and electronic structure have a significant influence on the CdO-based TCO crystal and band structure: (1) lattice parameters contract as a function of dopant ionic radii in the order Y (1.09 Å) <In (0.94 Å) <Sc (0.89 Å); (2) the carrier mobilities and doping efficiencies decrease in the order In > Y > Sc; (3) the dopant d state has substantial influence on the position and width of the s-based conduction band, which ultimately determines the intrinsic charge transport characteristics.

Original languageEnglish
Pages (from-to)8796-8804
Number of pages9
JournalJournal of the American Chemical Society
Volume127
Issue number24
DOIs
Publication statusPublished - Jun 22 2005

Fingerprint

Band structure
Oxides
Electronic structure
Glass
Charge transfer
Doping (additives)
Organic Chemicals
Bryophyta
Yttrium
Contracts
Thin films
Metals
Optical properties
Crystal structure
Temperature
Single crystals
Microstructure
Epitaxial films
Organic chemicals
Optical band gaps

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

CdO as the archetypical transparent conducting oxide. Systematics of dopant ionic radius and electronic structure effects on charge transport and band structure. / Yang, Yu; Jin, Shu; Medvedeva, Julia E.; Ireland, John R.; Metz, Andrew W.; Ni, Jun; Hersam, Mark C; Freeman, Arthur J; Marks, Tobin J.

In: Journal of the American Chemical Society, Vol. 127, No. 24, 22.06.2005, p. 8796-8804.

Research output: Contribution to journalArticle

@article{f4d57f0caf554da39bb1c1de3c5930fe,
title = "CdO as the archetypical transparent conducting oxide. Systematics of dopant ionic radius and electronic structure effects on charge transport and band structure",
abstract = "A series of yttrium-doped CdO (CYO) thin films have been grown on both amorphous glass and single-crystal MgO(100) substrates at 410 °C by metal-organic chemical vapor deposition (MOCVD), and their phase structure, microstructure, electrical, and optical properties have been investigated. XRD data reveal that all as-deposited CYO thin films are phase-pure and polycrystalline, with features assignable to a cubic CdO-type crystal structure. Epitaxial films grown on single-crystal MgO(100) exhibit biaxial, highly textured microstructures. These as-deposited CYO thin films exhibit excellent optical transparency, with an average transmittance of >80{\%} in the visible range. Y doping widens the optical band gap from 2.86 to 3.27 eV via a Burstein-Moss shift. Room temperature thin film conductivities of 8540 and 17 800 S/cm on glass and MgO(100), respectively, are obtained at an optimum Y doping level of 1.2-1.3{\%}. Finally, electronic band structure calculations are carried out to systematically compare the structural, electronic, and optical properties of the In-, Sc-, and Y-doped CdO systems. Both experimental and theoretical results reveal that dopant ionic radius and electronic structure have a significant influence on the CdO-based TCO crystal and band structure: (1) lattice parameters contract as a function of dopant ionic radii in the order Y (1.09 {\AA}) <In (0.94 {\AA}) <Sc (0.89 {\AA}); (2) the carrier mobilities and doping efficiencies decrease in the order In > Y > Sc; (3) the dopant d state has substantial influence on the position and width of the s-based conduction band, which ultimately determines the intrinsic charge transport characteristics.",
author = "Yu Yang and Shu Jin and Medvedeva, {Julia E.} and Ireland, {John R.} and Metz, {Andrew W.} and Jun Ni and Hersam, {Mark C} and Freeman, {Arthur J} and Marks, {Tobin J}",
year = "2005",
month = "6",
day = "22",
doi = "10.1021/ja051272a",
language = "English",
volume = "127",
pages = "8796--8804",
journal = "Journal of the American Chemical Society",
issn = "0002-7863",
publisher = "American Chemical Society",
number = "24",

}

TY - JOUR

T1 - CdO as the archetypical transparent conducting oxide. Systematics of dopant ionic radius and electronic structure effects on charge transport and band structure

AU - Yang, Yu

AU - Jin, Shu

AU - Medvedeva, Julia E.

AU - Ireland, John R.

AU - Metz, Andrew W.

AU - Ni, Jun

AU - Hersam, Mark C

AU - Freeman, Arthur J

AU - Marks, Tobin J

PY - 2005/6/22

Y1 - 2005/6/22

N2 - A series of yttrium-doped CdO (CYO) thin films have been grown on both amorphous glass and single-crystal MgO(100) substrates at 410 °C by metal-organic chemical vapor deposition (MOCVD), and their phase structure, microstructure, electrical, and optical properties have been investigated. XRD data reveal that all as-deposited CYO thin films are phase-pure and polycrystalline, with features assignable to a cubic CdO-type crystal structure. Epitaxial films grown on single-crystal MgO(100) exhibit biaxial, highly textured microstructures. These as-deposited CYO thin films exhibit excellent optical transparency, with an average transmittance of >80% in the visible range. Y doping widens the optical band gap from 2.86 to 3.27 eV via a Burstein-Moss shift. Room temperature thin film conductivities of 8540 and 17 800 S/cm on glass and MgO(100), respectively, are obtained at an optimum Y doping level of 1.2-1.3%. Finally, electronic band structure calculations are carried out to systematically compare the structural, electronic, and optical properties of the In-, Sc-, and Y-doped CdO systems. Both experimental and theoretical results reveal that dopant ionic radius and electronic structure have a significant influence on the CdO-based TCO crystal and band structure: (1) lattice parameters contract as a function of dopant ionic radii in the order Y (1.09 Å) <In (0.94 Å) <Sc (0.89 Å); (2) the carrier mobilities and doping efficiencies decrease in the order In > Y > Sc; (3) the dopant d state has substantial influence on the position and width of the s-based conduction band, which ultimately determines the intrinsic charge transport characteristics.

AB - A series of yttrium-doped CdO (CYO) thin films have been grown on both amorphous glass and single-crystal MgO(100) substrates at 410 °C by metal-organic chemical vapor deposition (MOCVD), and their phase structure, microstructure, electrical, and optical properties have been investigated. XRD data reveal that all as-deposited CYO thin films are phase-pure and polycrystalline, with features assignable to a cubic CdO-type crystal structure. Epitaxial films grown on single-crystal MgO(100) exhibit biaxial, highly textured microstructures. These as-deposited CYO thin films exhibit excellent optical transparency, with an average transmittance of >80% in the visible range. Y doping widens the optical band gap from 2.86 to 3.27 eV via a Burstein-Moss shift. Room temperature thin film conductivities of 8540 and 17 800 S/cm on glass and MgO(100), respectively, are obtained at an optimum Y doping level of 1.2-1.3%. Finally, electronic band structure calculations are carried out to systematically compare the structural, electronic, and optical properties of the In-, Sc-, and Y-doped CdO systems. Both experimental and theoretical results reveal that dopant ionic radius and electronic structure have a significant influence on the CdO-based TCO crystal and band structure: (1) lattice parameters contract as a function of dopant ionic radii in the order Y (1.09 Å) <In (0.94 Å) <Sc (0.89 Å); (2) the carrier mobilities and doping efficiencies decrease in the order In > Y > Sc; (3) the dopant d state has substantial influence on the position and width of the s-based conduction band, which ultimately determines the intrinsic charge transport characteristics.

UR - http://www.scopus.com/inward/record.url?scp=20944438705&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=20944438705&partnerID=8YFLogxK

U2 - 10.1021/ja051272a

DO - 10.1021/ja051272a

M3 - Article

VL - 127

SP - 8796

EP - 8804

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

IS - 24

ER -