Electronic synapses based on ultrathin quasi-two-dimensional gallium oxide memristor

Wang Shuopei^{1, 2}, He Congli^{1, 3, †}, Tang Jian^{1, 2}, Yang Rong^{1, 4}, Shi Dongxia^{1, 2, 4}, Zhang Guangyu^{1, 2, 4, 5, ‡}

(a) Schematic illustration of formation of a thin gallium oxide layer on liquid gallium surface under atmospheric condition. (b) The structure of gallium oxide. (c) Optical microscope image of gallium oxide on a SiO₂/Si wafer. Inset: AFM image of gallium oxide on SiO₂. (d)–(f) TEM characterization, with HRTEM images and SAED. (g), (h) XPS spectra of the gallium oxide and gallium/gallium oxide mix. (i) XPS spectra of SiO₂ substrate with and without GaO_x.