Scalable Integration of Coplanar Heterojunction Monolithic Devices on Two-Dimensional In₂Se₃

The formation of lateral heterojunction arrays within two-dimensional (2D) crystals is an essential step to realize high-density, ultrathin electro-optical integrated circuits, although the assembling of such structures remains elusive. Here we demonstrated a rapid, scalable, and site-specific integration of lateral 2D heterojunction arrays using few-layer indium selenide (In2Se3). We use a scanning laser probe to locally convert In2Se3 into In2O3, which shows a significant increase in carrier mobility and transforms the metal–semiconductor junctions from Schottky to ohmic type. In addition, a lateral p–n heterojunction diode within a single nanosheet is demonstrated and utilized for photosensing applications. The presented method enables high-yield, site-specific formation of lateral 2D In2Se3–In2O3-based hybrid heterojunctions for realizing nanoscale devices with multiple advanced functionalities.