Two-dimensional indium selenide wafers for integrated electronics

Two-dimensional (2D) indium selenide, with its low effective mass, high thermal velocity, and exceptional electronic mobility, is a promising semiconductor for surpassing silicon electronics, but grown films have not achieved performance comparable with that of exfoliated micrometer-scale flakes. We report a solid‒liquid‒solid strategy that converts amorphous indium selenide films into pure-phase, high-crystallinity indium selenide wafers by creating an indium-rich liquid interface and maintaining a strict 1:1 stoichiometric ratio of indium to selenium. The as-obtained indium selenide films exhibit exceptional uniformity, a pure phase, and a high crystallinity across an entire ~5-centimeter wafer. Transistor arrays based on the produced indium selenide wafers demonstrate outstanding electronic performance surpassing that of all 2D film-based devices, including an extremely high mobility (averaging as high as 287 square centimeters per volt-second) and a near-Boltzmann-limit subthreshold swing (averaging as low as 67 millivolts per decade) at room temperature.