Joint Mapping of Mobility and Trap Density in Colloidal Quantum Dot Solids


Stadler, Philipp
Sutherland, Brandon R.
Ren, Yuan
Ning, Zhijun
Simchi, Arash
Thon, Susanna M.
Hoogland, Sjoerd
Sargent, Edward H.

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Field-effect transistors have been widely used to study electronic transport and doping in colloidal quantum dot solids to great effect. However, the full power of these devices to elucidate the electronic structure of materials has yet to be harnessed. Here, we deploy nanodielectric field-effect transistors to map the energy landscape within the band gap of a colloidal quantum dot solid. We exploit the self-limiting nature of the potentiostatic anodization growth mode to produce the thinnest usable gate dielectric, subject to our voltage breakdown requirements defined by the Fermi sweep range of interest. Lead sulfide colloidal quantum dots are applied as the active region and are treated with varying solvents and ligands. In an analysis complementary to the mobility trends commonly extracted from field-effect transistor studies, we focus instead on the subthreshold regime and map out the density of trap states in these nanocrystal films. The findings point to the importance of comprehensively mapping the electronic band- and gap-structure within real quantum solids, and they suggest a new focus in investigating quantum dot solids with an aim toward improving optoelectronic device performance. © 2013 American Chemical Society.

Stadler P, Sutherland BR, Ren Y, Ning Z, Simchi A, et al. (2013) Joint Mapping of Mobility and Trap Density in Colloidal Quantum Dot Solids. ACS Nano 7: 5757–5762. Available:

This publication is based in part on work supported by an award (KUS-11-009-21) from the King Abdullah University of Science and Technology (KAUST), by the Ontario Research Fund Research Excellence Program, and by the Natural Sciences and Engineering Research Council (NSERC) of Canada. The authors thank O. Voznyy for his invaluable discourse.

American Chemical Society (ACS)

ACS Nano


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