Flexoelectric Thin-Film Photodetectors
Ming Wu, Zhizheng Jiang, Xiaojie Lou, Fan Zhang, Dongsheng Song, Shoucong Ning, Mengyao Guo, Stephen J. Pennycook, Jiyan Dai, Zheng Wen
Abstract
The flexoelectric effect, which manifests itself as a strain-gradient-induced electrical polarization, has triggered great interest due to its ubiquitous existence in crystalline materials without the limitation of lattice symmetry. Here, we propose a flexoelectric photodetector based on a thin-film heterostructure. This prototypical device is demonstrated by epitaxial LaFeO3 thin films grown on LaAlO3 substrates. A giant strain gradient of the order of 106/m is achieved in LaFeO3 thin films, giving rise to an obvious flexoelectric polarization and generating a significant photovoltaic effect in the LaFeO3-based heterostructures with nanosecond response under light illumination. This work not only demonstrates a novel self-powered photodetector different from the traditional interface-type structures, such as the p–n and Schottky junctions but also opens an avenue to design practical flexoelectric devices for nanoelectronics applications.