The functionalization of fine primary particles, including nanoparticles and nanotubes, is easily carried out using atomic or molecular layer deposition (ALD or MLD, respectively) techniques. Particle ALD/MLD can be used to deposit conformal and pinhole-free films of refractory oxides, non-oxides, metals, and hybrid polymer-based materials, amongst others. Fluidized bed reactors are well-suited for large scale operations and can be operated at reduced pressures while using inert gases necessary for standard self-limiting, flow-based ALD/MLD processes. The continuous-flow processing allows for process control using an inline mass spectrometer downstream from the reactor chamber. Many insulator and semiconductor films, including Al_2O_3, ZnO, TiO_2 and SiO_2 have been successfully deposited on primary particle surfaces in fluidized bed reactors using a variety of precursor types. The applications of functionalized or passivated nanomaterials are innumerable, and the flexibility of this scalable process demonstrates its economic viability.
展开▼
