Structures, influences, and formation mechanism of planar defects on (100), (001) and (−201) planes in β-Ga2O3 crystals

The β-Ga2O3 crystal is a significant ultrawide bandgap semiconductor with great potential in ultraviolet optoelectronics and high-power devices. Planar defects in β-Ga2O3 have been observed in experiments, but their structures, influences, formation mechanism, and controlling methods remain to be studied. We conducted a comprehensive study of β-Ga2O3 planar defects using density functional theory. We determined the atomic structures of planar defects (stacking faults and twins) on (100), (001), and (-201) planes in β-Ga2O3 crystals and calculated the formation energy and band structure of each defect. Our results indicate that the formation energy of stacking faults on the (100) plane and twins on the (100) and (-201) planes was extremely low, which explained why these planar defects were observed readily. We also studied the influence of common impurities (Si, Sn, Al, H) and vacancies in β-Ga2O3 crystals on the formation of these planar defects. Our findings revealed that specific impurities and vacancies could facilitate the formation of planar defects or even make them spontaneous. This research provides critical insights into the atomic structures of planar defects in β-Ga2O3, and explains why they form readily from the perspective of formation energy. These insights are important for future research into β-Ga2O3 defects.