A polar-switchable and controllable negative phototransistor for information encryption

/CIPS van der Waals (vdW) vertical heterostructures with a buried-gated architecture. The transistor exhibits NPC and positive photoconductance (PPC), demonstrating the significant role of ferroelectric polarization in the distinctive photoresponse. The observed inverse photoconductance can be attributed to the dynamic switching of ferroelectric polarization and interfacial charge transfer processes, which have been investigated experimentally and theoretically using Density Functional Theory (DFT). The unique phenomena enable the coexistence of controllable and polarity-switchable PPC and NPC. The novel feature holds tremendous potential for applications in optical encryption, where the specific gate voltages and light can serve as universal keys to achieve modulation of conductivity. The ability to manipulate conductivity in response to optical stimuli opens up new avenues for developing secure communication systems and data storage technologies. Harnessing this feature enables the design of advanced encryption schemes that rely on the unique properties of our material system. The study not only advances the development of NPC but also paves the way for more robust and efficient methods of optical encryption, ensuring the confidentiality and integrity of critical information in various domains, including data transmission, and information security.