Nanoscale Investigation of Grain Growth in RF-Sputtered Indium Tin Oxide Thin Films by Scanning Probe Microscopy

B. S. Lamsal, M. Dubey, V. Swaminathan, Y. Huh, D. Galipeau, Q. Qiao, Q. H. Fan

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


This work studied the electronic characteristics of the grains and grain boundaries of indium tin oxide (ITO) thin films using electrostatic and Kelvin probe force microscopy. Two types of ITO films were compared, deposited using radiofrequency magnetron sputtering in pure argon or 99% argon + 1% oxygen, respectively. The average grain size and surface roughness increased with substrate temperature for the films deposited in pure argon. With the addition of 1% oxygen, the increase in the grain size was inhibited above 150°C, which was suggested to be due to passivation of the grains by the excess oxygen. Electrostatic force microscopy and Kelvin probe force microscopy (KPFM) images confirmed that the grain growth was defect mediated and occurred at defective interfaces at high temperatures. Films deposited at room temperature with 1% oxygen showed crystalline nature, while films deposited with pure argon at room temperature were amorphous as observed from KPFM images. The potential drop across the grain and grain boundary was determined by taking surface potential line profiles to evaluate the electronic properties.

Original languageEnglish (US)
Pages (from-to)3965-3972
Number of pages8
JournalJournal of Electronic Materials
Issue number11
StatePublished - Nov 1 2014
Externally publishedYes


  • Indium tin oxide
  • Kelvin probe force microscopy
  • electrostatic force microscopy
  • thin film

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry


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