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

Abstract 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.