Biotite as a natural layered dielectric for two-dimensional transistors and memristors

The integration of natural layered minerals into van der Waals heterostructures offers a scalable and earth-abundant route to high-performance 2D electronics. Here, we explore biotite, an ion-rich member of the mica family, as a multifunctional building block in ultrathin device architectures. Mechanically exfoliated biotite flakes are incorporated as gate dielectrics in monolayer MoS 2 field-effect transistors, yielding low transfer hysteresis (20 mV) and field-effect mobilities around 10 cm 2 V −1 s −1 in all-van der Waals configurations with graphite contacts. The same platform supports high-performance photodetection, with responsivities up to 392 AW −1 and rise times of ~20 ms. Biotite is also implemented as an active switching material in metal-insulator-metal memristors, where silver filament formation drives reproducible bipolar resistive switching across more than 10 4 cycles with memory windows of 10 2 –10 4 Ω. By inverting the electrode bias configuration, the same device transitions from non-volatile to volatile threshold switching, which is especially relevant for neuromorphic device applications. Switching voltages scale with flake thickness, reaching below 0.5 V for 6 nm devices. Together, these findings reveal biotite as a promising natural layered 2D dielectric, unlocking new device functionalities in 2D transistors and memristors.