The integration of silicon (Si) and nanomaterials with infrared light harvesting capability is a promising approach to fabricate large area infrared light detecting arrays. However, the construction of a high quality junction between Si and small bandgap colloidal quantum dots (CQDs) remains a challenge, which limited their photodetecting performance in the short wavelength infrared region (1.4 μm–3 μm). Herein, a layer of solution processed ZnO nanoparticles was inserted between silicon and CQDs to passivate the surface dangling bond of silicon. This significantly reduces the carrier recombination between Si and CQDs. Meanwhile, the formation of the Si:CQD heterojunction structure enables effective carrier extraction. As a result, the photodetector shows the detecting range to the short wavelength infrared region (0.8 eV) and achieves a standard detectivity of 4.08 × 10¹¹ Jones at a bias of −0.25 V at room temperature.

Silicon is widespread in modern electronics, but its electronic bandgap prevents the detection of infrared radiation at wavelengths above 1,100 nanometers, which limits its applications in multiple fields such as night vision, health monitoring and space navigation systems. It is therefore of interest to integrate silicon with infrared-sensitive materials to broaden its detection wavelength. Here we demonstrate a photovoltage triode that can use silicon as the emitter but is also sensitive to infrared spectra owing to the heterointegrated quantum dot light absorber. The photovoltage generated at the quantum dot base region, attracting holes from silicon, leads to high responsivity (exceeding 410 A·W⁻¹ with V_bias of −1.5 V), and a widely self-tunable spectral response. Our device has the maximal specific detectivity (4.73 × 10¹³ Jones with V_bias of −0.4 V) at 1,550 nm among the infrared sensitized silicon detectors, which opens a new path towards infrared and visible imaging in one chip with silicon technology compatibility.