Hashemi, Mahdieh1; Farzad, Mahmood Hosseini3; Mortensen, N. Asger4; Xiao, Sanshui4
1 Structured Electromagnetic Materials, Department of Photonics Engineering, Technical University of Denmark2 Department of Photonics Engineering, Technical University of Denmark3 Shiraz University4 Center for Nanostructured Graphene, Center, Technical University of Denmark
Quantum efficiency of the silicon Schottky-barrier photodetector is limited by the weak interaction between the photons and electrons in the metal. By engineering the metal surfaces, metallic groove structures are proposed to achieve strong light absorption in the metal, where most of the energy is transferred into hot carriers near the Schottky barrier. The proposed broadband photodetector with a bi-grating metallic structure on the silicon substrate enables to absorb 76 % of the infrared light in the metal with a 200-nm bandwidth, while staying insensitive to the incident angle. These results pave a new promising way to attain high quantum efficiency silicon Schottky-barrier photodetectors.