Fabrication of Metal-Deposited Indium Tin Oxides

Its Applications to 385 nm Light-Emitting Diodes

Min Ju Kim, Tae Geun Kim

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

We report performance improvements in near-ultraviolet (NUV) light-emitting diodes (LEDs) using various metal-doped indium tin oxide (ITO/metals). Metals with an orbital energy gap greater than that of an In atom (e.g., Ti, Ga, Ge, and Al) are deposited on ITO, and subsequent annealing is performed to improve optical transmittance of ITO due to effective bandgap increase via the linear combination of atomic orbitals, as well as electrical conductivity; thus, current spreading via metal-doping effect at the surface of ITO. As a result, the ITO/metals (annealed at 550 °C, 1 min) exhibit 90.5-94.7% transmittance at 385 nm and a specific contact resistance of 2.1-3.0 × 10-3 Ω cm2, whereas the reference ITOs exhibit 76.5-89.5% and 3.2-4.5 × 10-3 Ω cm2, respectively. Compared to NUV LEDs using conventional ITO (60 nm), the InGaN/AlGaInN NUV LED using ITO (110 nm)/metal (3 nm) on average exhibits a 70% increase in light output power at 100 mA and a 2% decrease in forward voltage at 20 mA, with more uniform and brighter emission images. We also identified the origin for the improvement by analyzing the surface of ITO/metals using X-ray photoelectron spectroscopy and Auger electron spectroscopy. This approach could offer a simple, effective way to enhance the overall efficiency of conventional NUV LEDs using ITO.

Original languageEnglish
Pages (from-to)5453-5457
Number of pages5
JournalACS Applied Materials and Interfaces
Volume8
Issue number8
DOIs
Publication statusPublished - 2016 Mar 2

Fingerprint

Tin oxides
Indium
Light emitting diodes
Metals
Fabrication
Energy gap
Opacity
Auger electron spectroscopy
Contact resistance
indium tin oxide
X ray photoelectron spectroscopy
Doping (additives)
Annealing
Atoms
Ultraviolet Rays
Electric potential

Keywords

  • indium-tin-oxide
  • light-emitting diodes
  • metal-deposition
  • transmittance
  • ultraviolet

ASJC Scopus subject areas

  • Materials Science(all)

Cite this

Fabrication of Metal-Deposited Indium Tin Oxides : Its Applications to 385 nm Light-Emitting Diodes. / Kim, Min Ju; Kim, Tae Geun.

In: ACS Applied Materials and Interfaces, Vol. 8, No. 8, 02.03.2016, p. 5453-5457.

Research output: Contribution to journalArticle

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abstract = "We report performance improvements in near-ultraviolet (NUV) light-emitting diodes (LEDs) using various metal-doped indium tin oxide (ITO/metals). Metals with an orbital energy gap greater than that of an In atom (e.g., Ti, Ga, Ge, and Al) are deposited on ITO, and subsequent annealing is performed to improve optical transmittance of ITO due to effective bandgap increase via the linear combination of atomic orbitals, as well as electrical conductivity; thus, current spreading via metal-doping effect at the surface of ITO. As a result, the ITO/metals (annealed at 550 °C, 1 min) exhibit 90.5-94.7{\%} transmittance at 385 nm and a specific contact resistance of 2.1-3.0 × 10-3 Ω cm2, whereas the reference ITOs exhibit 76.5-89.5{\%} and 3.2-4.5 × 10-3 Ω cm2, respectively. Compared to NUV LEDs using conventional ITO (60 nm), the InGaN/AlGaInN NUV LED using ITO (110 nm)/metal (3 nm) on average exhibits a 70{\%} increase in light output power at 100 mA and a 2{\%} decrease in forward voltage at 20 mA, with more uniform and brighter emission images. We also identified the origin for the improvement by analyzing the surface of ITO/metals using X-ray photoelectron spectroscopy and Auger electron spectroscopy. This approach could offer a simple, effective way to enhance the overall efficiency of conventional NUV LEDs using ITO.",
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