Galliumnitriidi

Galliumnitriidi, known in English as gallium nitride (GaN), is a wide-bandgap semiconductor with the chemical formula GaN. It has a direct bandgap of about 3.4 eV at room temperature and a hexagonal wurtzite crystal structure. GaN exhibits a high breakdown electric field (around 3.3 MV/cm), relatively high electron mobility for a wide-bandgap material, and good thermal conductivity (about 130 W/m·K). These properties enable devices that operate at higher voltages, temperatures, and frequencies than silicon-based technologies.

Growth and substrates are central to GaN technology. GaN is grown by methods such as metal-organic chemical vapor deposition (MOCVD), hydride vapor phase epitaxy (HVPE), and molecular beam epitaxy (MBE). Common substrates include sapphire, silicon carbide (SiC), and silicon, though lattice mismatch with these substrates introduces defects and dislocations that can affect performance.

Doping and device challenges are notable. Achieving reliable p-type doping is difficult; magnesium is used but can create deep acceptor levels and compensating defects. N-type doping is more straightforward, using silicon or germanium. These doping issues influence fabrication and the performance of GaN-based devices.

Applications of GaN are broad. It enables blue and white light-emitting diodes (LEDs) and ultraviolet LEDs, as well as laser diodes. In power electronics and radio frequency (RF) fields, GaN-based high-electron-mobility transistors (HEMTs) offer high efficiency, high-frequency operation, and compact form factors for power converters and communications equipment.

History and impact are marked by rapid development in the 1990s that led to practical blue LEDs and, later, white lighting. The achievements in GaN research were recognized with the Nobel Prize in Physics in 2014 for Akasaki, Amano, and Nakamura.