Spatial Control of Optical Emission and Conductivity in Molybdenum Oxide through Electron-Beam Irradiation

Deterministic spatial control of material properties is essential for advanced electronic and optoelectronic device technologies. van der Waals (vdW) materials stand out for their high tunability, yet achieving multifunctional on-chip control remains challenging. Here, we focus on α-MoO₃ and site-selectively modulate both its optical emission and conductivity via electron-beam irradiation. <i>In situ</i> cathodoluminescence spectroscopy reveals a cumulative enhancement of blue emission under the beam, exhibiting superlinear increases in intensity with beam current. Irradiated regions show distinct contrasts in Raman and work functions, indicating oxygen defect formation. Moreover, these local structural modifications substantially increase lateral and vertical conductivities, enabling conductive channels with sharp boundaries. Building on this, we demonstrate stable, deterministic optical patterning with subdiffraction spatial resolution, highlighting the potential for submicron devices without chemical processes or traditional lithography. Our results provide a versatile platform for on-chip light sources, conductive interconnects, and customizable optoelectronic elements, expanding the design space of vdW materials.