Electron transport in quantum dot solids: Monte Carlo simulations of the effects of shell filling, Coulomb repulsions, and site disorder

R. E. Chandler, A. J. Houtepen, J. Nelson, and D. Vanmaekelbergh
Phys. Rev. B 75, 085325 – Published 28 February 2007
PDFHTMLExport Citation

Abstract

A Monte Carlo model is developed for the hopping conductance in arrays of quantum dots (QDs). Hopping is simulated using a continuous time random walk algorithm, incorporating all possible transitions, and using a nonresonant electron-hopping rate based on broadening of the energy levels through quantum fluctuations. Arrays of identical QDs give rise to electronic conductance that depends strongly upon level filling. In the case of low charging energy, metal insulator transitions are observed at electron occupation levels, n, that correspond to the complete filling of an S, P, or D shell. When the charging energy becomes comparable to the level broadening, additional minima in conductance appear at integer values of n, as a result of electron-electron repulsion. Disorder in QD diameters leads to disorder in the energy levels, resulting in washing out of the structure in the dependence of conductance on n and a net reduction in conductance. Simulation results are shown to be consistent with experimental measurements of conductance in arrays of zinc oxide and cadmium selenide QDs that have different degrees of size disorder, and the degree of size disorder is quantified. Simulations of the temperature dependence of conductance show that both Coulombic charging and size disorder can lead to activated behavior and that size disorder leads to conductance that is sublinear on an Arrhenius plot.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Received 12 October 2006

DOI:https://doi.org/10.1103/PhysRevB.75.085325

©2007 American Physical Society

Authors & Affiliations

R. E. Chandler1, A. J. Houtepen2, J. Nelson1, and D. Vanmaekelbergh2

  • 1Department of Physics, Imperial College London, Prince Consort Road, London SW7 2BW, United Kingdom
  • 2Debye Institute, Utrecht University, Princetonplein 1, 3508 TA, Utrecht, The Netherlands

Article Text (Subscription Required)

Click to Expand

Supplemental Material (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 75, Iss. 8 — 15 February 2007

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review B

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×