Growth of Monolayer WS₂ Lateral Homojunctions via <i>In Situ</i> Domain Engineering

Two-dimensional (2D) lateral homojunctions possess unique geometries and properties distinct from those of other heterostructures, including perfect lattice matching and clean carrier diffusion channels, showing great potential in beyond-silicon nanoelectronics. However, the direct growth of 2D lateral homojunctions within the same crystal phase and layer remains challenging due to the limited choice of elements. Here, we report the epitaxy growth of semiconducting monolayer WS₂ lateral homojunctions by <i>in situ</i> domain engineering during chemical vapor deposition (CVD). Domain-selective defects independently modulate the electronic structures of different regions, enabling the integration of intrinsic D-/E-mode field-effect transistors within one channel. Moreover, multiple characterizations demonstrated that optimized band alignment with an ideal lattice match exists at the interface, endowing homojunctions with strong diode-like characteristics. Benefiting from the unique atomic structures, the monolayer homojunctions were used to construct homo-NMOS logic devices. The sub-1 nm-thick inverter with good rail-to-rail operation shows a peak voltage gain of 12, a dynamic delay time about 135 μs, and a peak power consumption as low as 1.3 nW. This approach paves a new way for <i>in situ</i> engineering both defect configurations and distributions within atomic layers, offering comprehensive understanding of 2D landscape as well as accelerating their potential applications.