Parametric study on controllable growth of SrZrS₃ thin films with good conductivity for photodetectors

SrZrS₃ is a promising chalcogenide perovskite with unique advantages including high abundance of consisting elements, high chemical stability, strong light absorption above its direct band gap, and excellent carrier transport ability. While unfortunately, due to the lack of breakthroughs in its thin film synthesis technique, its optoelectronic properties are not fully investigated, not to mention the device applications. In this work, large-area and uniform SrZrS₃ thin film (5 cm × 5 cm) was prepared by facile sputtering method, followed by a post-annealing treatment at a high temperature of 1000 °C for 2–12 h under CS₂ atmosphere. All SrZrS₃ samples prepared adopt distorted orthorhombic structure with pnma space group and have high crystallinity. In addition, the band gap of SrZrS₃ thin film is measured to be 2.29 eV, higher than that of the powder form (2.06 eV). Importantly, the light absorption coefficient of SrZrS₃ thin film reaches over 10⁵ cm⁻¹, and the carrier mobility is as high as 106 cm²/(V∙s). The above advantages allow us to use the SrZrS₃ thin film as photoactive layer for photodetector applications. Finally, a symmetrically structured photoconductive detector was fabricated, performing a high responsivity of 8 A/W (405 nm light excitation). These inspiring results promise the glorious application potential of SrZrS₃ thin film in photodetectors, solar cells, and other optoelectronic devices.