Power Devices

α-Ga₂O₃ has been considered a promising material for efficient power semiconductors because of its large band gap. Sapphire can be an appropriate substrate for α-Ga₂O₃ because the two materials have same crystal structure. However, it is hard to obtain high-quality α-Ga₂O₃ thin films on sapphire due to a large lattice mismatch. We study on the selective growth of α-Ga₂O₃ thin films on top of stripe-patterned sapphire nanomembranes. The thin substrate enables to boost crystal quality of thin films by sharing strain so-called strain partitioning effect. We also develop various patterns suitable for obtaining more high-quality thin films and developing high-performance optoelectrical devices.

Gallium Oxide (Ga₂O₃), with wide-bandgap of 5.0–5.3 eV and UV transparency has the great potential to fabricate the high-power device and ultraviolet solar-blind photodetectors (DUV PDs). In this work, by using low-cost, vacuum-free mist chemical vapor deposition method, we successfully obtained high-quality Ga₂O₃ single crystal thin film with reduced threading dislocations and fabricated Schottky diode reveals enhanced breakdown voltage. Also, the UV photodetector with nanostructured antireflective surface exhibit highly responsivity, detectivity, and external quantum efficiency (EQE). This high device performance based on Ga₂O₃ pave a way for high-power devices, next-generation UV photodetectors.