High-performance uncooled PbSe/CdSe nanostructured mid-infrared photodetector with tunable cutoff wavelength.

This article focuses on the design and fabrication of room-temperature (RT) high-performance mid-wavelength infrared (MWIR) photoconductors based on Lead Selenide (PbSe)/Cadmium Selenide (CdSe) heterostructure nanocrystals grown via vapor phase deposition (VPD) on silicon dioxide/silicon substrates. The devices demonstrate tunable absorption edges at 3.75 and 4.0 μm, external quantum efficiencies exceeding 100% indicative of photoconductive gain, and RT peak specific detectivities (D*) of 2.17 × 10¹⁰ and 1.61 × 10¹⁰ Jones, respectively. Oxygen annealing enhances sensitivity by inducing electron traps that increase carrier lifetime, while noise analysis reveals 1/f noise as the dominant source, consistent with Hooge’s empirical relation for homogeneous semiconductors. The study highlights the potential of VPD-grown PbSe/CdSe photoconductors for scalable, low-cost MWIR detection with improved uniformity and integration prospects compared to conventional chemical bath deposition methods.