The Role of Passivants on the Stoichiometry of CdSe and GaAs Nanocrystals

• Published in: Journal of physical chemistry. C 2013-10, Vol.117 (42), p.21981-21987
• Main Authors: Debnath, Saikat, Cherian, Roby, Mahadevan, Priya
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Materials science; Methods of nanofabrication; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures; Physics
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp401798y

Passivating molecules are introduced during the growth of semiconductor nanocrystals (NCs) to arrest their growth leading to nanoparticles of a desired size. In order to carry out this function, they bind to the surface atoms of the NC, removing any band gap states in the process. While they have been observed to play a role in modifying various other physical properties of materials, in this work we consider examples of two well-known binary semiconductors, GaAs and CdSe, and find within our calculations that the passivating ligands can play an important role in stabilizing highly nonstoichiometric semiconductors. This has important implications in the observed optical and electronic properties of binary semiconductor NCs where usually no suitable passivant exists for the anion.