Refractive Index of ITO, Indium Tin Oxide, InSnO

Indium Tin Oxide (ITO, or more properly Tin doped Indium Oxide) is a very common transparent conductive oxide (TCO) film. It may reasonably be described as an alloy of In2O3 and SnO2. This material has extremely complicated refractive indices with optical absorption in both the UV and NIR regions. ITO is used extensively in most commercial flat panel displays and touch screens. While it is dependable and widespread, ITO cannot be called an optically invariant material. Each manufacturers’ ITO films have slightly to widely different refractive indices. Further complicating the optical description of such films is ITO’s well known graded index behavior. This is particularly noticeable when ITO films are deposited at thicknesses above 100nm. It becomes quite obvious that the complex refractive indices change as one moves in the z (thickness) direction of the film. In such cases, simple (spatially independent) index models will not adequately mimic the spectral reflectance data.

For a typical sample of ITO the refractive index and extinction coefficient at 632.8 nm are 1.858 and 0.058. Below are files of complete refractive index and extinction coefficients. If the file is not available for download, you can request our proprietary file by clicking "Request".

  • Tab-delimited data file for unrestricted use
Wavelength (nm)

Refractive Index Reference - Sopra Material Database

Wikipedia: Indium Tin Oxide

No guarantee of accuracy - use at your own risk.