A solution-processed octahedral nano-blocks structure CaIn₂S₄film for UV/vis photodetection

A novel CaIn₂S₄with three-dimensional octahedral nano-blocks (ONBs) are successfully synthesized on fluorine-doped tin oxide (FTO) substrate by a simple hydrothermal method. The CaIn₂S₄ONBs are uniform grown and scattered on the whole FTO substrate with high regular and symmetric morphology as well as average diagonal length of about 600 nm. Based on the as-synthesized CaIn₂S₄ONBs, a photodetector (PD) is fabricated. Satisfyingly, it is found that the CaIn₂S₄ONBs PD achieves a broad-band response ranging from ultraviolet (UV) to visible ( vis) light at zero bias voltage. It is also significant that the CaIn₂S₄ONBs PD enables a fast response, in which the rise time and decay time are less than 0.15 and 0.2 s, respectively. Furthermore, the morphological evolution of the CaIn₂S₄ONBs and plausible UV/vis detection mechanism of the CaIn₂S₄ONBs PD are discussed.