The integration of high-dielectric-constant (high-κ) materials with two-dimensional (2D) semiconductors is promising to overcome performance limitations and reach their full theoretical potential. Here we show that naturally occurring phlogopite mica, exfoliated into ultrathin flakes, can serve as a robust high-κ dielectric layer for transition metal dichalcogenide-based 2D electronics and optoelectronics. Phlogopite's wide bandgap (~4.8 eV), high dielectric constant (~11), and large breakdown field (10 MVcm−1) enable transistors with subthreshold swings down to 100 mVdec−1, minimal hysteresis (30-60 mV) and interface trap densities comparable to state-of-the-art oxide dielectrics. Moreover, phototransistors built upon monolayer molybdenum disulfide (MoS2) and phlogopite exhibit responsivities up to 3.3x104 AW−1 and detectivities near 1010 Jones, surpassing devices based on conventional gate insulators. We further demonstrate the versatility of this natural dielectric by integrating phlogopite/MoS2 heterostructures into NMOS inverters, showcasing robust voltage gains and low-voltage operation. Our findings establish phlogopite as a promising, earth-abundant dielectric for next-generation 2D transistor technologies and high-performance photodetection.
@article{arxiv.2505.09461,
title = {Natural layered phlogopite dielectric for ultrathin two-dimensional optoelectronics},
author = {Thomas Pucher and Julia Hernandez-Ruiz and Guillermo Tajuelo-Castilla and José Ángel Martín-Gago and Carmen Munuera and Andres Castellanos-Gomez},
journal= {arXiv preprint arXiv:2505.09461},
year = {2025}
}