Unexpected Large Electrostatic Gating by Pyroelectric Charge Accumulation

作者：Yicheng Mou, Qi Liu, Jiaqi Liu, Yingchao Xia, Zejing Guo, Wenqing Song, Jiaming Gu, Zixuan Xu, Wenbin Wang, Hangwen Guo, Wu Shi, Jian Shen, Cheng Zhang · 发表于：Nano Letters · 年份：2025 · DOI：10.1021/acs.nanolett.5c00099 · 被引用次数：5 · 研究领域：Ferroelectric and Negative Capacitance Devices、Semiconductor materials and devices、Advanced Memory and Neural Computing

Pyroelectricity refers to the accumulation of charges due to changes in the spontaneous polarization of ferroelectric materials when subjected to temperature variations. Typically, these pyroelectric charges are considered unstable and dissipate quickly through interactions with the external environment. Consequently, the pyroelectric effect has been largely overlooked in ferroelectric field-effect transistors. In this work, we leverage the van der Waals interface of hBN to achieve a substantial and long-term electrostatic gating effect in graphene devices via the pyroelectric properties of a ferroelectric LiNbO 3 substrate. Upon cooling, the polarization change in LiNbO 3 induces high doping concentrations of up to 10 13 cm –2 in the adjacent graphene. Through a combination of transport measurements and noncontact techniques, we demonstrate that the pyroelectric charge accumulation, as well as its enhancement in electric fields, are responsible for this unexpectedly high doping level. Our findings introduce a novel mechanism for voltage-free electrostatic gating control with long retention.