High‐Performance Inverse Opal SnO 2 /Te 0.4 Se 0.6 Photodetector for Optical Communication and Health Monitoring

Abstract Recently, Te 1‐x Se x films have attracted extensive attention from researchers, owing to their distinctive crystal structures and tunable bandgaps. Particularly, Te 1‐x Se x films hold considerable promise for application in the field of photoelectric detection. However, the Te 1‐x Se x photodetectors face challenges related to inadequate light absorption and high dark current, which hinder their device performance. Here, a Te 0.4 Se 0.6 film onto a well‐organized monolayer inverse opal SnO 2 (i‐SnO 2 ) substrate is deposited using low‐pressure chemical vapor deposition, creating a vertical heterojunction with unique interfacial contact. This innovative structure exhibits significant optical coupling phenomena, enhancing both the light capture and carrier transport capabilities of the Te 0.4 Se 0.6 film. The FTO/i‐SnO 2 /Te 0.4 Se 0.6 /Ag device exhibits excellent self‐powered photoelectric properties, featuring a broad‐spectrum response range of 254–1050 nm. Notably, at a bias voltage of 0 V, the device achieves an exceptionally low dark current density of just 0.3 nA cm −2 . This low dark current enables the device to attain a remarkable on‐off current ratio of 3 × 10 4 , an outstanding detectivity of 5.2 × 10 9 Jones, and a linear dynamic range exceeding 91 dB for 850 nm light illumination. Furthermore, the FTO/i‐SnO 2 /Te 0.4 Se 0.6 /Ag device demonstrates potential applications in the fields of optical communication and health monitoring. The work provides a new strategy for developing integrated multi‐functional photodetection.