Indium nitride
Indium nitride (InN) is a semiconductor with a very small bandgap, about 0.65–0.7 eV at room temperature, which makes it responsive to infrared light. This property, along with high electron mobility, makes InN interesting for solar cells and high-speed electronics.
InN has a wurtzite (hexagonal) crystal structure. Its bandgap can be tuned by mixing with gallium nitride to form indium gallium nitride (InGaN), giving a direct bandgap that spans from infrared (about 0.69 eV) to ultraviolet (about 3.4 eV). The material can be studied for solar-energy applications because its bandgap can be matched to parts of the solar spectrum.
Key challenges include p-type doping and growing high-quality indium-rich InGaN, as well as heteroepitaxial growth with GaN or AlN. Thin layers of InN can be grown using metalorganic chemical vapor deposition (MOCVD).
Some InN thin films can be highly conductive and even superconductive at very low temperatures. The observed superconductivity depends on the film’s structure and carrier density, and magnesium doping can raise the superconducting transition temperature to around 4 K. The superconductivity is thought to involve metallic indium chains or nanoclusters and can survive in moderate magnetic fields.
Safety: InN is an irritant and reacts with water to form ammonia, so proper handling and safety precautions are needed.
Quick facts:
- Formula: InN
- Structure: wurtzite (hexagonal)
- Density: about 6.81 g/cm³; Melting point: ~1100 °C
- Bandgap: ~0.65–0.7 eV (300 K); InGaN range: 0.69–3.4 eV
- Refractive index: ~2.9
- Applications: solar cells, high-speed electronics
- Growth: thin films by MOCVD
- Notable: can exhibit high conductivity and superconductivity at very low temperatures (Tc ~ up to 4 K with Mg doping)
This page was last edited on 2 February 2026, at 23:40 (CET).