Advanced Semiconductor Technology Laboratory
In recent years, hydrogen has been intensively researched as a clean source of renewable energy to replace the existing petroleum-based fuels. Therefore, hydrogen sensor development is rapidly becoming important for issues concerning industrial safety and environmental protection. Gallium nitride (GaN) has an extremely low intrinsic carrier concentration owing to its wide energy bandgap property, which allows the semiconductor properties to be maintained at much higher temperatures than those of conventional semiconductor materials, such as Si and GaAs. This would also result in low leakage currents and stable operation at elevated temperatures, which are typically required for hydrogen catalytic reactions. When an AlGaN/GaN heterojunction is employed in a sensor platform, the polarization induced two-dimensional electron gas (2DEG) channel formed at the interface between the AlGaN and GaN provides the additional benefit of high sensitivity owing to the thin AlGaN barrier layer and high electron mobility. We are developing high sensitivity hydrogen sensors based on GaN platform.