Near-infrared photoluminescence radiation from the interface of an annealed ZnO nano thin film/silicon heterostructure array

In this study, the photoluminescence (PL) features of an annealed ZnO nano thin film/silicon heterostructure array were investigated. PL spectra were observed, which were closely related to the annealing temperature and covered visible–near infrared (NIR) region among 500–900 nm (1.37 eV–1.59 eV), especially two unexpected NIR peaks at 1.44 eV, 1.57 eV were detected. silicon array was synthesized by hydrothermal corrosion by using the solution composed of ferric nitrate and hydrofluoric acid. A regular array surface was obtained and exhibited a red PL emission with a slight position shift as the excitation wavelength varied. Oxygen defects in the array structure and silicon nanoparticles were responsible for the red PL. ZnO nano thin film/silicon heterostructure array was prepared by heating the Zn film coated array, which was obtained by magnetron sputtering. As the heating temperature increased to 350–400 °C, the PL intensity of the ZnO nano thin film/silicon heterostructure array decreased to approximately half that of the original, and the orange-red PL peaks was substituted by NIR radiations gradually. The models of electrons transition at the interface were analyzed to explain the emissions. The results demonstrated that the potential of ZnO/silicon heterostructure array as a NIR-emitting material.