Surface Adsorption-Assisted Visible and Near-Infrared Photodetection in SrTiO3 Nanostructures

Abstract

Perovskites are relatively less explored materials in the domain of visible and near-infrared (NIR) photodetection. This study represents high-performance visible and NIR photodetection by using SrTiO3 nanostructures. Two nanoforms of SrTiO3, that is, nanograss and hollow spheres, were synthesized by a cost-effective facial hydrothermal route. The SrTiO3 nanoforms were then characterized using various microscopic and spectroscopic techniques to ensure their morphology, structures, crystallinity, and chemical compositions. Thin films of SrTiO3 nanostructures were then deposited on a Au interdigitized electrode-based SiO2/Si substrate by the spray-coating technique to fabricate the photodetectors. Both the SrTiO3 nanostructures, that is, grass- and hollow sphere-based photodetectors, were characterized under visible (532 nm) and NIR (905) light radiation. The grass/hollow sphere showed a responsivity of 1.6/0.4736 mA/W and a detectivity of 13.62 × 109/10.83 × 109 Jones in visible light. Under NIR illumination, responsivity and detectivity were measured as 2.42/0.1936 mA/W and 21.58 × 109/5.32 × 109 Jones for grass/hollow sphere samples, respectively. Overall, the SrTiO3 grass nanostructure showed relatively better photoresponse both in the visible and NIR regions. Both the SrTiO3 nanostructures exhibited highly stable photodetection after a long period of time. The sensors were then tested in vacuum and compared with ambient air to confirm the strong influence of surface adsorption of the oxygen species in photoresponse.