Refractive index database

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Optical constants of GaN (Gallium nitride)
Kawashima et al. 1997: thin film; n,k 0.124–0.992 µm

Wavelength: µm

Complex refractive index (n+ik)[ i ]

n   k   LogX   LogY   eV

Derived optical constants

Conditions & Spec sheet

n_is_absolute: true
wavelength_is_vacuum: true
substrate: sapphire


Single-crystalline hexagonal GaN (α-GaN) film on (0001) sapphire substrate. Ordinary ray (o, E⊥c). Room temperature.


1) T. Kawashima, H. Yoshikawa, S. Adachi. Optical properties of hexagonal GaN, J. Appl. Phys. 82, 3528-3535 (1997)
2) S. Logothetidis, J. Petalas, M. Cardona, T. D. Moustakas. Optical properties and temperature dependence of the interband transitions of cubic and hexagonal GaN, Phys. Rev. B 50, 18017-18029 (1994)
* Authors of Ref. 1 provide a simplified model of the interband transitions (MDF) based on their experimental data combined with experimental data from Ref. 2.
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Gallium nitride, GaN

Gallium nitride (GaN) is a binary III/V direct bandgap semiconductor commonly used in light-emitting diodes (LEDs) for both general lighting and displays. With a wide bandgap of about 3.4 eV, GaN is also highly valued for its thermal stability, which makes it particularly useful in high-power and high-frequency applications. It is an essential material in the fabrication of high-electron-mobility transistors (HEMTs) and is increasingly used in high-frequency and high-power radar and communication systems. GaN has gained prominence in optoelectronics, specifically in the development of blue LEDs, which led to energy-efficient white LEDs and was recognized with the 2014 Nobel Prize in Physics. It is often grown on substrates like sapphire or silicon carbide, although the industry is moving towards native GaN substrates for higher performance.

Other name

  • Gallium(III) nitride

External links