Ab initio calculation of electronic transport properties between PbSe quantum dots facets with halide ligands (Cl, Br, I)

The transport properties between PbSe quantum dots (100) facets with three different halide ligands (e.g., chloride, bromide, and iodide) and iodide ligand at (001), (110), (111) facets have been studied using density functional theory (DFT) and non-equilibrium Green's function (NEGF). Quantum conductance between iodide ligand attached surfaces has the highest value due to its extra ligand contribution near Fermi level. However, configurations with bromide and chloride ligands have much higher maximum quantum conductance due to their stronger coupling between surfaces with lower distances. The electrical fields formed between PbSe(110) surfaces attenuates the charge transport whereas between (111) surfaces it improves the transport near fermi level. In spite of the existence of electrical field and lower surface to surface distance, the zero-voltage bias transport between (001) surfaces is stronger. This is possibly understood from the slight increase in the DOS from the Pb s-orbital and Se p-orbital near Fermi level. (C) 2018 The Japan Society of Applied Physics.