Negative Photoconductivity in Liquid-Metal-Derived Ultrathin 2D Ceria-Rich Oxide Nanosheets for Broadband Photodetection

Abstract

Engineering two-dimensional (2D) ultrathin oxides through in situ control during growth enables functional materials to be realized from systems whose bulk crystals are nonlayered and unsuitable for conventional exfoliation. Liquid-metal chemistry provides such a route by using liquid gallium as a solvent and growth medium, allowing added metal atoms to participate directly in surface-oxide formation, while yielding continuous and smooth nanoscale 2D sheets with preserved morphological integrity. Cerium oxide, despite its broad relevance in sensing, catalysis, and optoelectronics, has remained largely unexplored as a stratified 2D oxide because its parent phases are nonlayered and difficult ..