Metal-insulator transition in a semiconductor nanocrystal network

Benjamin L. Greenberg, Zachary L. Robinson, Yilikal Ayino, Jacob T. Held, Timothy A. Peterson, K. Andre Mkhoyan, Vlad S. Pribiag, Eray S. Aydil, Uwe R. Kortshagen

Research output: Contribution to journalArticle

Abstract

Many envisioned applications of semiconductor nanocrystals (NCs), such as thermoelectric generators and transparent conductors, require metallic (nonactivated) charge transport across an NC network. Although encouraging signs of metallic or near-metallic transport have been reported, a thorough demonstration of nonzero conductivity, s, in the 0 K limit has been elusive. Here, we examine the temperature dependence of s of ZnO NC networks. Attaining both higher s and lower temperature than in previous studies of ZnO NCs (T as low as 50 mK), we observe a clear transition from the variable-range hopping regime to the metallic regime. The critical point of the transition is distinctly marked by an unusual power law close to s ∝ T1/5. We analyze the critical conductivity data within a quantum critical scaling framework and estimate the metal-insulator transition (MIT) criterion in terms of the free electron density, n, and interparticle contact radius, r.

Original languageEnglish (US)
Article numbereaaw1462
JournalScience Advances
Volume5
Issue number8
DOIs
StatePublished - Aug 23 2019

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)
  • General

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    Greenberg, B. L., Robinson, Z. L., Ayino, Y., Held, J. T., Peterson, T. A., Andre Mkhoyan, K., Pribiag, V. S., Aydil, E. S., & Kortshagen, U. R. (2019). Metal-insulator transition in a semiconductor nanocrystal network. Science Advances, 5(8), [eaaw1462]. https://doi.org/10.1126/sciadv.aaw1462