Colloidal InSb Quantum Dots Mid-Wave Infrared Photoconductive Detectors via One-Step Strong Acid Surface Treatment...

Colloidal InSb quantum dots (QDs) hold significant promise in infrared photodetection. However, the current InSb QDs suffer from poor carrier mobility and limited spectral response (<1.8 μm) due to complex surface structure and high sensitivity to hydrolysis and oxidation. Here, we demonstrate one-step strong acid surface treatment strategy to simultaneously replace native insulating ligands and eliminate surface indium oxide. This dual-functional strategy achieves efficient surface passivation and enhances charge carrier transport, enabling InSb QDs films to exhibit an unprecedented hole mobility of 1.4 cm² V^-1 s^-1. Notably, we report the first realization of a broadband InSb QDs infrared photoconductive detector with spectral sensitivity extending beyond 3 μm at room temperature. The device exhibits a specific detectivity of 4.7 × 10⁷ Jones at 3.0 μm, representing the longest-wavelength interband photodetection based on lead/mercury-free QDs reported to date. This work manifests an important step toward room-temperature operable and heavy-metal-free QDs based mid-wave infrared photodetectors.