Indium gallium aluminium nitride (InGaAlN, AlInGaN) is a GaN-based compound semiconductor. It is usually prepared by epitaxial growth, such as metalorganic chemical vapour deposition (MOCVD), molecular-beam epitaxy (MBE), pulsed laser deposition (PLD), etc.[1] This material is used for specialist opto-electronics applications, often in blue laser diodes and LEDs.