Schottky hot-electron photodetector by cavity-enhanced optical Tamm resonance

We propose a design of Schottky-junction hot-electron photodetector under purely planar configuration, which is composed by a front distributed Bragg reflector (DBR), a metal/semiconductor (Au/Si) Schottky junction, and a metallic rear reflector. With such a hybrid design, optical Tamm resonance (i.e., a surface state) can be excited near the DBR/Au interface and significantly enhanced due to the presence of the metallic cavity. The intense Tamm resonance shows a strong field localization to the incident photon energy, enabling a high hot-electron generation for sensitive photodetection. Finite-element and rigorous coupled-wave simulations verify that both optical Tamm state and Fabry-Perot cavity mode can be excited simultaneously, which exhibit a high tunability by tailoring either the DBR or the metallic cavity. With a good angular performance, the proposed design shows an optical absorption in the top thin Au layer over 89%, leading to a 30-fold enhancement in the photoresponsivity compared to that of the normal Au/Si Schottky system.