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Title: Design of low surface roughness-low residual stress-high optoelectronic merit a-IZO thin films for flexible OLEDs

Abstract

The development of efficient and reliable large-area flexible optoelectronic devices demands low surface roughness-low residual stress-high optoelectronic merit transparent conducting oxide (TCO) thin films. Here, we correlate surface roughness-residual stress-optoelectronic properties of sputtered amorphous indium zinc oxide (a-IZO) thin films using a statistical design of experiment (DOE) approach and find a common growth space to achieve a smooth surface in a stress-free and high optoelectronic merit a-IZO thin film. The sputtering power, growth pressure, oxygen partial pressure, and RF/(RF+DC) are varied in a two-level system with a full factorial design, and results are used to deconvolve the complex growth space, identifying significant control growth parameters and their possible interactions. The surface roughness of a-IZO thin film varies over 0.19 nm to 3.97 nm, which is not in line with the general assumption of low surface roughness in a-IZO thin films. The initial regression model and analysis of variance reveal no single optimum growth sub-space to achieve low surface roughness (=0.5 nm), low residual stress (-1 to 0 GPa), and industrially acceptable electrical conductivity (>1000 S/cm) for a-IZO thin films. The extrapolation of growth parameters in light of the current results and previous knowledge leads to a new sub-space, resulting inmore » a low residual stress of -0.52 +/- 0.04 GPa, a low surface roughness of 0.55 +/- 0.03 nm, and moderate electrical conductivity of 1962 +/- 3.84 S/cm in a-IZO thin films. Lastly, these results demonstrate the utility of the DOE approach to multi-parameter optimization, which provides an important tool for the development of flexible TCOs for the next-generation flexible organic light emitting diodes applications.« less

Authors:
 [1];  [2]; ORCiD logo [3]; ORCiD logo [1]
  1. Indian Institute of Technology Ropar, Punjab (India)
  2. Colorado School of Mines, Golden, CO (United States)
  3. National Renewable Energy Lab. (NREL), Golden, CO (United States)
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
OSTI Identifier:
1329995
Report Number(s):
NREL/JA-5K00-67324
Journal ID: ISSN 0021-8979
Grant/Contract Number:  
AC36-08GO28308
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 119; Journal Issue: 22; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; thin film growth; surface measurements; thin film roughness; electrical conductivity; organic light emitting diodes; OLED; amorphous indium zinc oxide; surface roughness; residual stress; design of experiments (DOE); analysis of variance(ANOVA)

Citation Formats

Kumar, Naveen, Wilkinson, Taylor M., Packard, Corinne E., and Kumar, Mukesh. Design of low surface roughness-low residual stress-high optoelectronic merit a-IZO thin films for flexible OLEDs. United States: N. p., 2016. Web. https://doi.org/10.1063/1.4953212.
Kumar, Naveen, Wilkinson, Taylor M., Packard, Corinne E., & Kumar, Mukesh. Design of low surface roughness-low residual stress-high optoelectronic merit a-IZO thin films for flexible OLEDs. United States. https://doi.org/10.1063/1.4953212
Kumar, Naveen, Wilkinson, Taylor M., Packard, Corinne E., and Kumar, Mukesh. Wed . "Design of low surface roughness-low residual stress-high optoelectronic merit a-IZO thin films for flexible OLEDs". United States. https://doi.org/10.1063/1.4953212. https://www.osti.gov/servlets/purl/1329995.
@article{osti_1329995,
title = {Design of low surface roughness-low residual stress-high optoelectronic merit a-IZO thin films for flexible OLEDs},
author = {Kumar, Naveen and Wilkinson, Taylor M. and Packard, Corinne E. and Kumar, Mukesh},
abstractNote = {The development of efficient and reliable large-area flexible optoelectronic devices demands low surface roughness-low residual stress-high optoelectronic merit transparent conducting oxide (TCO) thin films. Here, we correlate surface roughness-residual stress-optoelectronic properties of sputtered amorphous indium zinc oxide (a-IZO) thin films using a statistical design of experiment (DOE) approach and find a common growth space to achieve a smooth surface in a stress-free and high optoelectronic merit a-IZO thin film. The sputtering power, growth pressure, oxygen partial pressure, and RF/(RF+DC) are varied in a two-level system with a full factorial design, and results are used to deconvolve the complex growth space, identifying significant control growth parameters and their possible interactions. The surface roughness of a-IZO thin film varies over 0.19 nm to 3.97 nm, which is not in line with the general assumption of low surface roughness in a-IZO thin films. The initial regression model and analysis of variance reveal no single optimum growth sub-space to achieve low surface roughness (=0.5 nm), low residual stress (-1 to 0 GPa), and industrially acceptable electrical conductivity (>1000 S/cm) for a-IZO thin films. The extrapolation of growth parameters in light of the current results and previous knowledge leads to a new sub-space, resulting in a low residual stress of -0.52 +/- 0.04 GPa, a low surface roughness of 0.55 +/- 0.03 nm, and moderate electrical conductivity of 1962 +/- 3.84 S/cm in a-IZO thin films. Lastly, these results demonstrate the utility of the DOE approach to multi-parameter optimization, which provides an important tool for the development of flexible TCOs for the next-generation flexible organic light emitting diodes applications.},
doi = {10.1063/1.4953212},
journal = {Journal of Applied Physics},
number = 22,
volume = 119,
place = {United States},
year = {2016},
month = {6}
}

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Works referenced in this record:

Past achievements and future challenges in the development of optically transparent electrodes
journal, November 2012


Transparent Conducting Oxides for Photovoltaics
journal, March 2007

  • Fortunato, Elvira; Ginley, David; Hosono, Hideo
  • MRS Bulletin, Vol. 32, Issue 03, p. 242-247
  • DOI: 10.1557/mrs2007.29

Transparent conducting oxide semiconductors for transparent electrodes
journal, March 2005


Solution processing of transparent conductors: from flask to film
journal, January 2011

  • Pasquarelli, Robert M.; Ginley, David S.; O'Hayre, Ryan
  • Chemical Society Reviews, Vol. 40, Issue 11, p. 5406-5441
  • DOI: 10.1039/c1cs15065k

High-Performance Organic Light-Emitting Diodes Using ITO Anodes Grown on Plastic by Room- Temperature Ion-Assisted Deposition
journal, February 2004


Highly efficient organic light-emitting diodes from delayed fluorescence
journal, December 2012

  • Uoyama, Hiroki; Goushi, Kenichi; Shizu, Katsuyuki
  • Nature, Vol. 492, Issue 7428
  • DOI: 10.1038/nature11687

Criteria for ITO (indium–tin-oxide) thin film as the bottom electrode of an organic light emitting diode
journal, May 2002


Indium tin oxide films prepared by radio frequency magnetron sputtering method at a low processing temperature
journal, November 2000


Bending Fatigue Study of Sputtered ITO on Flexible Substrate
journal, November 2011

  • Alzoubi, Khalid; Hamasha, Mohammad M.; Lu, Susan
  • Journal of Display Technology, Vol. 7, Issue 11
  • DOI: 10.1109/JDT.2011.2151830

Durability study on sputtered indium tin oxide thin film on Poly Ethylene Terephthalate substrate
journal, July 2011


Evaporated Sn‐doped In 2 O 3 films: Basic optical properties and applications to energy‐efficient windows
journal, December 1986

  • Hamberg, I.; Granqvist, C. G.
  • Journal of Applied Physics, Vol. 60, Issue 11
  • DOI: 10.1063/1.337534

Amorphous ITO thin films prepared by DC sputtering for electrochromic applications
journal, December 2002


On the homogeneity of sputter-deposited ITO films Part I. Stress and microstructure
journal, October 1995


Electrical and optical properties of electron beam evaporated ITO thin films
journal, October 2000


Substrate temperature effect on transparent heat reflecting nanocrystalline ITO films prepared by electron beam evaporation
journal, July 2010

  • Fallah, Hamid Reza; Ghasemi varnamkhasti, Mohsen; Vahid, Mohammad Javad
  • Renewable Energy, Vol. 35, Issue 7
  • DOI: 10.1016/j.renene.2009.10.034

The Remarkable Thermal Stability of Amorphous In-Zn-O Transparent Conductors
journal, October 2008

  • Taylor, Matthew P.; Readey, Dennis W.; van Hest, Maikel F. A. M.
  • Advanced Functional Materials, Vol. 18, Issue 20
  • DOI: 10.1002/adfm.200700604

The electrical, optical and structural properties of In x Zn 1− x O y (0  x  1) thin films by combinatorial techniques
journal, December 2004

  • Taylor, Matthew P.; Readey, Dennis W.; Teplin, Charles W.
  • Measurement Science and Technology, Vol. 16, Issue 1
  • DOI: 10.1088/0957-0233/16/1/012

Organic light-emitting diode on indium zinc oxide film prepared by ion assisted deposition dc sputtering system
journal, April 2002


Stable Bending Performance of Flexible Organic Light-Emitting Diodes Using IZO Anodes
journal, September 2013

  • Kwak, Kiyeol; Cho, Kyoungah; Kim, Sangsig
  • Scientific Reports, Vol. 3, Issue 1
  • DOI: 10.1038/srep02787

Characteristics of indium zinc oxide films deposited using the facing targets sputtering method for OLEDs applications
journal, September 2010


Optimizing amorphous indium zinc oxide film growth for low residual stress and high electrical conductivity
journal, October 2013


Radio-frequency superimposed direct current magnetron sputtered Ga:ZnO transparent conducting thin films
journal, May 2012

  • Sigdel, Ajaya K.; Ndione, Paul F.; Perkins, John D.
  • Journal of Applied Physics, Vol. 111, Issue 9
  • DOI: 10.1063/1.4709753

Low-stress indium–tin–oxide thin films rf magnetron sputtered on polyester substrates
journal, September 2002

  • Carcia, P. F.; McLean, R. S.; Reilly, M. H.
  • Applied Physics Letters, Vol. 81, Issue 10
  • DOI: 10.1063/1.1504874

Effects of Energetic Ion Bombardment on Structural and Electrical Properties of Al-Doped ZnO Films Deposited by RF-Superimposed DC Magnetron Sputtering
journal, July 2010

  • Ito, Norihiro; Oka, Nobuto; Sato, Yasusi
  • Japanese Journal of Applied Physics, Vol. 49, Issue 7
  • DOI: 10.1143/JJAP.49.071103

A simple model for the formation of compressive stress in thin films by ion bombardment
journal, April 1993


Room-temperature fabrication of transparent flexible thin-film transistors using amorphous oxide semiconductors
journal, November 2004

  • Nomura, Kenji; Ohta, Hiromichi; Takagi, Akihiro
  • Nature, Vol. 432, Issue 7016, p. 488-492
  • DOI: 10.1038/nature03090

Working hypothesis to explore novel wide band gap electrically conducting amorphous oxides and examples
journal, May 1996


Influence of dc magnetron sputtering parameters on surface morphology of indium tin oxide thin films
journal, January 2004


Electrical and structural properties of In-doped ZnO films deposited by RF superimposed DC magnetron sputtering system
journal, April 2010

  • Park, Ji Bong; Park, Se Hun; Song, Pung Keun
  • Journal of Physics and Chemistry of Solids, Vol. 71, Issue 4
  • DOI: 10.1016/j.jpcs.2009.12.062

    Works referencing / citing this record:

    High performance, flexible and room temperature grown amorphous Ga 2 O 3 solar-blind photodetector with amorphous indium-zinc-oxide transparent conducting electrodes
    journal, June 2019

    • Kumar, Naveen; Arora, Kanika; Kumar, Mukesh
    • Journal of Physics D: Applied Physics, Vol. 52, Issue 33
    • DOI: 10.1088/1361-6463/ab236f

    Role of oxygen and boron to control the duality behavior and thermal stability in Boron doped amorphous indium-zinc-oxide thin films
    journal, April 2019

    • Kumar, Naveen; Arora, Kanika; Kumar, Mukesh
    • Semiconductor Science and Technology, Vol. 34, Issue 5
    • DOI: 10.1088/1361-6641/ab086a