InP Quantum Dot Fabrication Using Aminophosphine Precursors and Size-Sorting

The patent divides the quantum dot fabrication process into distinct stages: core formation using aminophosphine precursors, followed by separate shell growth stages. This segmentation allows optimization of each stage independently, maintaining the cost and safety advantages of aminophosphine precursors while achieving high emission efficiency through controlled shell formation that narrows the size distribution and improves optical properties

The patent creates composite core-shell structures where the core is formed from In and P precursors and the shell consists of additional semiconductor materials. This composite approach allows the core to benefit from the cost-effective and safe aminophosphine-based synthesis while the shell provides the necessary optical confinement and surface passivation to achieve high quantum yield and narrow FWHM

The patent performs preliminary size-selection of the InP cores before shell formation. By pre-sorting the cores based on size, the subsequent shell growth process becomes simpler and more controlled, as each shell formation step can be optimized for a specific size range. This preliminary action reduces the overall process complexity while achieving narrow FWHM and high quantum yield

The patent systematically varies key parameters including precursor ratios, reaction temperature, injection rate, and shell thickness to optimize the quantum dot properties. By carefully controlling these parameters during core formation and shell growth, the method achieves high quantum yield and narrow FWHM through a structured approach that manages process complexity