Gallium nitride ( ) is a very hard material, commonly found in bright LEDs since the 1990s.

The compound is a direct-bandgap semiconductor material of wurtzite crystal structure, with a wide (3.4 eV) band gap, used in optoelectronic, high-power and high-frequency devices. It is a binary group III/group V direct bandgap semiconductor. Its sensitivity to ionizing radiation is low (like other group III nitrides), making it a suitable material for solar cell arrays for satellites. Because GaN transistors can operate at much hotter temperatures and work at much higher voltages than GaAs transistors, they make ideal power amplifiers at microwave frequencies.