Ultrawide-bandgap semiconductor AlN crystals: growth and applications

In recent years, ultrawide bandgap semiconductor materials represented by aluminum nitride (AlN) have attracted worldwide attention due to their excellent high-frequency power characteristics, stable high-temperature performance, low energy loss, and good ultraviolet (UV) transmittance. They have great application prospects in the fields of high-efficiency optoelectronic devices, high-power and high-frequency electronic devices, ultra-high voltage power electronic devices, deep UV warning and guidance, and deep UV-LED disinfection. The physical vapor transport (PVT) method has the advantages of a simple growth process, fast growth rate, and high crystal integrity, and has gradually become one of the most effective methods for growing bulk AlN crystals. This review systematically summarizes the latest research progress in AlN crystals grown by the PVT method in recent years, and introduces their applications in deep UV-LEDs, UV lasers and Schottky barrier diodes (SBDs). Finally, the challenges and application prospects of AlN crystals are discussed. As an important new type of direct bandgap ultrawide bandgap semiconductor material, AlN crystals have shown extremely important strategic application value. The output power of deep UV-LED devices meets practical requirements, and high-power electronic power devices are still in the verification stage. From the perspective of material superiority, they have considerable development potential. This review systematically summarizes the latest research advances of AlN crystals grown by the PVT method and their applications.