LAUSR

Performance of plamson induced hot electrons based photodetectors largely relies on the photon absorption capability. To improve the optical absorption, many perfect absorbers based on the periodic metallic nanostructures have been designed and fabricated through low-throughput, costly and time-consuming lithographic processes, which seriously limit the future potential applications of plasmonic hot-electron optoelectronics devices. Here, a large-scale, broadband absorber consisting of ITO film, ZnO layer, Au film and Al nanospike arrays substrate was designed and fabricated for hot electrons based photodetection. The new designed absorber's absorptivity can beup to 70% in the broad wavelength range from 400 nm to 800 nm(even up to 90% in the wavelength range from 400-550nm) and most of the absorption comes from the Au film, which is effective for the generation of hot electrons. The enhanced broadband absorption is ascribed to the SPPs mode and LSPR mode supported by the nanospike arrays. The influence of geometry and material parameters on the optical absorption properties is also specifically investigated through numerical simulation. The efficient and broadband absorption of nanospikes device resulting in much larger photocurrent compared with that of planar reference device. Our approach which is compatible with large-scale manufacturing, paves the way for the practical implementation of hot-electrons based optoelectronic devices.