Writing Multi-Compositional Heterostructure in 2D Materials

<b>Abstract.</b> Spatial confinement drives most quantum effects in semiconductors. In two-dimensional (2D) materials, the gifted confinement along the out-of-plane direction enables a plethora of quantum effects and unprecedented properties. Extra degrees of confinement within the plane of 2D materials requires the development of advanced material synthesis methods combined with state-of-the-art nanofabrication techniques. Towards this goal, the formation of lateral junctions between heterogeneous 2D materials has been intensely pursed. However, the degree of spatial confinements offered by available techniques is far from dimensions at which quantum effects start to emerge. Here, we present a technique that enables the synthesis of lateral heterostructures with dimensions as small as a few tens of nanometers, with any desired geometries, in isolated or periodic fashions, in predefined locations, and with tunable material compositions. The prospect of our technique for applications including photovoltaics and optoelectronics will be discussed.