higherbandgap

Higher bandgap refers to semiconducting materials in which the energy difference between the valence and conduction bands is larger than that of conventional silicon devices. The bandgap energy, Eg, governs how readily electrons can be excited, which in turn affects optical absorption, electrical conductivity, and device performance. Materials with higher bandgaps, commonly called wide-bandgap semiconductors, typically have Eg above about 2–3 eV at room temperature. Notable examples include gallium nitride (GaN, ~3.4 eV), silicon carbide (SiC, ~3.0–3.3 eV depending on polytype), aluminum nitride (AlN, ~6.2 eV), gallium oxide (Ga2O3, ~4.8–5.0 eV), and diamond (~5.5 eV).

Properties and implications. Higher bandgap materials usually exhibit higher breakdown electric fields and lower intrinsic carrier concentrations, enabling devices that operate at higher voltages and temperatures with reduced leakage. This makes them attractive for power electronics, radio frequency applications, and high-temperature electronics. They also offer wide ultraviolet transparency and are favorable for ultraviolet light emitters and detectors. However, the large bandgap also means lower absorption in the visible and near-infrared, which can complicate solar energy applications and require specialized growth, doping, and device architectures.

Challenges and development. Key engineering challenges include achieving reliable and controllable doping (particularly p-type), growing high-quality crystals or films, and integrating these materials with existing substrates and fabrication processes. Ongoing research focuses on improving material quality, contact formation, and scalable manufacturing to extend the use of higher bandgap materials in commercial devices.

See also bandgap; wide-bandgap semiconductors; power electronics.