Precise preparation of two-dimensional heterostructures via chemical vapor deposition: Current status and future prospects

<sec>This review systematically summarizes recent advances in the chemical vapor deposition (CVD)-based synthesis of two-dimensional (2D) heterostructures, which have emerged as an ideal platform for next-generation optoelectronic and microelectronic devices due to their ability to integrate diverse material components and induce novel physical phenomena. The review begins by introducing the classification of 2D heterostructures, such as vertical (VHS), lateral (LHS), and hybrid heterostructures (HHS). We further highlight the unique advantages of CVD as a key route for achieving large-area, high-quality, and controllable preparation, thereby effectively avoiding interface contamination and issues such as interfacial states and Fermi-level pinning caused by lattice mismatch in traditional semiconductor heterostructures.</sec><sec>We focus on four core strategies for precise growth control: precursor design, temperature field modulation, vapor composition control, and substrate engineering. In the precursor design, by constructing core-shell structures, introducing auxiliary agents, or modulating precursor proportions and physical forms, the sequential supply and reaction pathways of different components can be precisely regulated to guide oriented growth and suppress alloy formation. In temperature field modulation, utilizing differences in the growth windows between various materials and precisely controlling heating rates, temperature uniformity, and gradients can achieve selective growth modes (lateral or vertical), effective suppression of alloying, and protection of pre-deposited layers. In vapor composition control, by switching carrier gas atmospheres, the nucleation and growth of specific materials can be selectively initiated or halted, providing a one-pot strategy for fabricating multi-junction lateral heterostructures and superlattices with atomically sharp interfaces. In substrate engineering, the surface energy, lattice matching, catalytic activity, and pretreatment processes of different substrates are used to actively guide nucleation sites, growth modes, and crystalline quality.</sec><sec>Although significant progress has been made in the CVD synthesis of various 2D heterostructures, such as <i>MX</i>₂/<i>MY</i>₂, graphene/h-BN, and mixed-dimensional heterojunctions, considerable challenges remain in achieving large-area uniformity, reproducible processes, precise control of complex heterostructures (e.g., multi-interface, moiré superlattices, and patterned growth), and compatibility with current semiconductor technology. Future development should focus on integrating in situ characterization, multi-scale simulations, and artificial intelligence-assisted optimization to facilitate a transition from empirical trial-and-error to precision design. The introduction of novel growth techniques, such as laser-induced or microwave-assisted CVD, roll-to-roll processes, and substrate interface engineering, is expected to accelerate the practical application of 2D heterostructures in cutting-edge fields such as quantum computing and flexible electronics.</sec>