Electron tunneling characteristics of a cubic quantum dot, (PbS){sub 32}

• Published in: The Journal of chemical physics 2013-12, Vol.139 (24)
• Main Authors: Gupta, Sanjeev K., Banyai, Douglas, Pandey, Ravindra, He, Haiying, Kandalam, Anil K.
• Format: Article
• Language: English
• Subjects: CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ELECTRIC CONDUCTIVITY; ELECTRONS; FERMI LEVEL; LEAD SULFIDES; QUANTUM DOTS; SCANNING TUNNELING MICROSCOPY; SUBSTRATES; TUNNEL EFFECT
• ISSN: 0021-9606; 1089-7690
• DOI: 10.1063/1.4849136

The electron transport properties of the cubic quantum dot, (PbS){sub 32}, are investigated. The stability of the quantum dot has been established by recent scanning tunneling microscope experiments [B. Kiran, A. K. Kandalam, R. Rallabandi, P. Koirala, X. Li, X. Tang, Y. Wang, H. Fairbrother, G. Gantefoer, and K. Bowen, J. Chem. Phys. 136(2), 024317 (2012)]. In spite of the noticeable energy band gap (∼2 eV), a relatively high tunneling current for (PbS){sub 32} is predicted affirming the observed bright images for (PbS){sub 32}. The calculated I-V characteristics of (PbS){sub 32} are predicted to be substrate-dependent; (PbS){sub 32} on the Au (001) exhibits the molecular diode-like behavior and the unusual negative differential resistance effect, though this is not the case with (PbS){sub 32} on the Au (110). Appearance of the conduction channels associated with the hybridized states of quantum dot and substrate together with their asymmetric distribution at the Fermi level seem to determine the tunneling characteristics of the system.