Analysis of ErAs nanoparticle surface grown using a two-step modified diffusion length process

Erbium arsenide nanoparticles (ErAs NPs) grown using a two-step modified diffusion length growth process are studied. The process consists of a low diffusion length (LDL) deposition step for nucleation followed by a high diffusion length (HDL) deposition step for the growth of existing nuclei without forming new nuclei. With the LDL and HDL growth conditions properly coordinated, independent control over the NP size is demonstrated over a wide range of NP densities (14–309 NP/μm2). This control is attributed to the change of Peclet number between the LDL and HDL steps, which enables complete capture of the adatoms by the existing nuclei. The appropriate LDL and HDL growth conditions are identified for practical applications of the process. Given the uniqueness of the process, the ErAs nucleus critical size (∼7 Er atoms) is derived in the nucleation regime in the LDL step exhibiting consistency with the previous observation for ErAs NP growth.