High-Performance Solar Blind UV Photodetectors Based on Single-Crystal Si/β-Ga₂O₃ p-n Heterojunction

In this study, Si/β-Ga₂O₃ solar-blind photodetectors (PDs) have been demonstrated via micro-transfer printing of a single crystalline Si pillar on β-Ga₂O₃. Unlike other previous approaches for β-Ga₂O₃ based heterojunction, this new single crystalline p-n Si/β-Ga₂O₃ heterojunction has a particle-free heterointerface and does not show any sign of internal strain after the heterogeneous integration that is confirmed by Raman spectroscopy. As a result, PDs exhibit extremely high photoresponsivity (748 A W⁻¹), quantum efficiency (3.67 × 10⁵%), and UV/visible rejection ratio (≈10⁵) under UV light illumination. This result is believed to provide a viable route for the realization of high-performance solar-blind photodetection systems, which form some of the most indispensable and important components in high-performance next-generation security, biomedical, and environmental monitoring systems. Also, the unique heterogeneous integration method allows us to realize a variety of β-Ga₂O₃ based heterostructures that can further enhance the optical performances of β-Ga₂O₃ based PDs.