Excitonic Complexes of Tetrahedral InAs and InP Quantum Dots

Tetrahedral III–V semiconductor quantum dots (QDs) have recently emerged as promising cadmium-free nanomaterials for optoelectronic, quantum-photonic, and bioimaging applications. However, despite rapid progress in their synthesis, the intrinsic many-body excitonic properties that govern their optical response remain largely unexplored. In this work we employ an atomistic empirical pseudopotential and screened configuration-interaction (EPM–SCI) framework to investigate the electronic structure, optical absorption, and multiparticle states of ideally passivated tetrahedral InAs and InP quantum dots (QDs) with edge lengths ranging from 2 to 14 nm. The calculated single-exciton transition energies of tetrahedral InP QDs agree closely with available experimental data, whereas the InAs results are consistent with our benchmark TDDFT calculations and reproduce the established size dependence of spherical InAs QDs. At equivalent edge lengths, the exciton binding energy remains larger in InP than in InAs. Biexcitons remain bound throughout the investigated size range, with binding energies of approximately 5–30 meV. Within the ideal-passivation and dielectric-screening model employed here, positive trions remain bound in both materials, whereas negative trions are bound in InAs but antibound in InP. Our results establish a theoretical benchmark for interpreting future experiments and provide fundamental design principles for tetrahedral III–V quantum dots for advanced optoelectronic and quantum-photonic applications.