Two-dimensional (2D) materials such as transition metal chalcogenides can be used to create different components of electronic devices, including semiconducting channels and metallic electrodes and interconnects. However, devices are typically fabricated using a step-by-step process that can introduce defects and impurities, leading to a reduction in device performance. Here we show that 2D electronic components can be chemically synthesized and integrated simultaneously in a single step, creating 2D devices in which each component in the active layer is connected via covalent bonds instead of physical interfaces. The approach involves the phase-patterned growth of atomic layers, and, using 2D molybdenum ditelluride (MoTe 2 ) as the active material, we show that it can be used to construct high-performance field-effect transistors (FETs) and arrays of logic devices. We also use the technique to construct FETs with ultrashort gate lengths, bilayered FETs with vertical interconnections and flexible devices.

Atomically dispersed catalysts refer to substrate-supported heterogeneous catalysts featuring one or a few active metal atoms that are separated from one another. They represent an important class of materials ranging from single-atom catalysts (SACs) and nanoparticles (NPs). While SACs and NPs have been extensively reported, catalysts featuring a few atoms with well-defined structures are poorly studied. The difficulty in synthesizing such structures has been a critical challenge. Here we report a facile photochemical method that produces catalytic centers consisting of two Ir metal cations, bridged by O and stably bound to a support. Direct evidence unambiguously supporting the dinuclear nature of the catalysts anchored on α-Fe₂O₃ is obtained by aberration-corrected scanning transmission electron microscopy (AC-STEM). Experimental and computational results further reveal that the threefold hollow binding sites on the OH-terminated surface of α-Fe₂O₃ anchor the catalysts to provide outstanding stability against detachment or aggregation. The resulting catalysts exhibit high activities toward H₂O photooxidation.