GaN

Gallium nitride (GaN) is a wide-bandgap semiconductor with a direct bandgap of about 3.4 eV at room temperature. It most commonly crystallizes in the wurtzite structure, though zinc blende can be achieved in metastable forms. GaN enables devices that operate at higher voltages, temperatures, and frequencies than traditional semiconductors.

Key properties include a high breakdown field, strong chemical stability, and high thermal conductivity, which together support efficient, robust devices. The material’s direct bandgap makes it effective for optoelectronic applications, while its high breakdown field and electron mobility in certain heterostructures, such as AlGaN/GaN, enable high-power and high-frequency electronic devices.

GaN is grown by methods such as metal-organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE) on substrates including sapphire, silicon carbide, and silicon. Lattice and thermal expansion mismatches necessitate buffer layers and surface engineering; GaN-on-Si is pursued for cost and scalability, though defects and dislocations remain challenges. Thermal management is important in high-power devices due to GaN’s strong heat generation.

Applications span optoelectronics and power electronics. GaN-based light-emitting diodes produce blue and white light and are used in displays and signaling; laser diodes and UV detectors also employ GaN. In electronics, GaN high-electron-mobility transistors enable compact, efficient power converters, RF amplifiers, and fast-switching devices for charging, data centers, and electric vehicles.

GaN’s development was pivotal to blue LEDs, a achievement recognized with the Nobel Prize in Physics in 2014. Ongoing research aims to improve material quality, manufacturability, and integration with other semiconductor platforms.