Photosensitivity of the PbS Colloidal Quantum Dot-Based Nanostructures with an Energy Barrier

A new architecture of photosensitive elements for the near- (0.7–1.4 μm) and short-wavelength (1.4–3.0 μm) infrared spectral ranges is proposed, which is based on hybrid nanostructures consisting of PbS colloidal quantum dots and ZnO and silver nanowire functional layers. Small-sized (12 × 12 μm) photosensitive elements with an energy barrier at the contact between layers of colloidal quantum dots with n- and p‑type conductivity have been studied. The I‒V characteristics, spectral dependences of optical absorption, and relative spectral photosensitivity S_i(λ)/S_i(λ_max) of the barrier structures at room temperature have been examined. It is shown that the proposed architecture of the barrier structures ensures the photosensitivity in a wide spectral range from 0.4 to 2.0 µm. An excess of the average value of the relative spectral sensitivity S_i(λ)/S_i(λ_max) by a factor of about 1.5 as compared with the values observed previously for the PbS colloidal quantum dot barrier nanostructures in the wavelength range of 0.9–1.85 μm has been found.