Reconfigurable Polarized Photodetector with Centrosymmetric Silicon Enabled by Flexoelectric Effect for Encrypted Communication

Abstract

In the rapidly evolving digital landscape, secure communication is crucial, and polarization-sensitive photodetectors offer a promising approach to enhance security and efficiency. However, conventional devices face limitations in encoding capacity due to material-specific anisotropic properties and geometric factors. In this study, the critical role of the flexoelectric effect in detecting polarized light in silicon and its effective utilization in secure communication systems are demonstrated. The device shows self-biased photoresponse, which is modulated by up to 320% with the application of force by a sharp probe, a phenomenon attributed to the flexoelectric effect. The polarization sensing behavior is confirmed through comprehensive scanning photocurrent mapping, which is further supported by rigorous finite element simulations. As a potential application, the device is implemented to sense Morse code and effectively modulate it using the flexoelectric effect and light polarization angle, offering more sophisticated encryption methods for secure communication. This research provides valuable insights for advancing secure communication technologies and overcoming the inherent challenges associated with silicon-based photodetectors.