Gas-Phase Assembly of Semiconductor Nanostructures into Functional Field-Effect Transistors

Conventional semiconductor manufacturing relies on top-down lithography, which faces fundamental limitations in resolution, material versatility, and cost at the nanoscale. While bottom-up colloidal strategies offer alternative pathways, they are constrained by ligand contamination and insufficient precision for integrated circuits. Here a gas-phase synthesis and assembly platform is reported that overcomes these challenges by combining plasma-generated, stabilizer-free semiconductor nanoparticles (NPs) with electric-field-guided 3D nanoprinting. This approach begins to generate sub-5-nm NPs (Si, Ge, ZnO, In₂O₃, GaAs, SiC) with high purity (no ligands) and monodispersity, enabled by kinetically controlled nucleation in a dilute inert gas stream. Deterministic assembly is also achieved via coupled gas-flow and electric-field topologies, acting as "virtual nozzles" to direct NPs into architectures with <10-nm alignment precision-surpassing colloidal methods and rivaling lithographic resolution. For functional FET integration, gate modulation (ON/OFF ratio: ≈1211) and carrier mobility (8.33 cm² V^-1 s^-1) are demonstrated, validated through cross-characterization. Mechanistic studies reveal that NP coalescence is governed by surface-dynamics control, where gas-phase confinement arrests Ostwald ripening to enable swallowing of coming NPs in nanoprinting. The method's dry, ligand-free nature ensures material purity and enables air-sensitive semiconductors (e.g., GaAs). By bridging the gap between top-down precision and bottom-up versatility, this work establishes a scalable pathway for 3D-printed nanoelectronics and advances the synthetic toolbox for semiconductor nanomaterials.