Deriving 2D in-plane heterostructures in TMDC nanosheets via electron beam irradiation

2D in-plane heterostructures can enhance the electronic performance of hybrid systems, allowing for a variety of electronic device applications. However, precisely achieving uniform in-plane heterostructures with seamless interfaces at the same atomic planes remains a challenge. In this work, 2D in-plane heterostructures were successfully fabricated through electron beam irradiation-induced phase transformation in transition metal dichalcogenides (TMDCs). The transformed phases were seamlessly connected to the pristine TMDCs, forming ultraclean and atomically sharp interfaces of heterostructures. The phases were stable and determined to be novel tetragonal-like atomic structures by experimental and theoretical analyses. In situ transmission electron microscopy revealed that the phase transition involved atomic loss, lattice contraction, and then significant structural reconstruction in the pristine TMDCs. These results demonstrate that electron irradiation can efficiently achieve precise manufacturing of 2D in-plane heterostructures, offering new opportunities for the development of high-quality 2D in-plane heterostructures and novel 2D devices with high performance.