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.