Cao Aiping, Li Shubing, Chen Hongli, Deng Menghan, Xu Xionghu, Shang Liyan, Li Yawei, Cui Anyang, Hu Zhigao
Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics & Advanced Instrument (Ministry of Education), Department of Physics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
Key Laboratory of Optoelectronic Material and Device, Department of Physics, Shanghai Normal University, Shanghai 200234, China.
Mater Horiz. 2023 Oct 30;10(11):5099-5109. doi: 10.1039/d3mh01120h.
Anomalous negative phototransistors have emerged as a distinct research area, characterized by a decrease in channel current under light illumination. Recently, their potential applications have been expanded beyond photodetection. Despite the considerable attention given to negative phototransistors, negative photoconductance (NPC) in particular remains relatively unexplored, with limited research advancements as compared to well-established positive phototransistors. In this study, we designed ferroelectric field-effect transistors (FeFETs) based on the WSe/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.
反常负光电晶体管已成为一个独特的研究领域，其特点是在光照下沟道电流会减小。最近，它们的潜在应用已扩展到光探测之外。尽管负光电晶体管受到了相当多的关注，但特别是负光电导（NPC）仍相对未被充分探索，与成熟的正光电晶体管相比，研究进展有限。在本研究中，我们基于具有埋入栅极结构的WSe/CIPS范德华（vdW）垂直异质结构设计了铁电场效应晶体管（FeFET）。该晶体管表现出NPC和正光电导（PPC），证明了铁电极化在独特光响应中的重要作用。观察到的反向光电导可归因于铁电极化的动态切换和界面电荷转移过程，我们已使用密度泛函理论（DFT）对其进行了实验和理论研究。这种独特现象使得可控且极性可切换的PPC和NPC能够共存。这一新颖特性在光学加密应用中具有巨大潜力，其中特定的栅极电压和光可作为通用密钥来实现电导率调制。响应光刺激来操纵电导率的能力为开发安全通信系统和数据存储技术开辟了新途径。利用这一特性能够设计出依赖于我们材料系统独特性质的先进加密方案。该研究不仅推动了NPC的发展，还为更强大、高效的光学加密方法铺平了道路，确保了包括数据传输和信息安全在内的各个领域关键信息的保密性和完整性。
