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Joint mapping of mobility and trap density in colloidal quantum dot solids

Stadler, P ; Sharif University of Technology | 2013

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  1. Type of Document: Article
  2. DOI: 10.1021/nn401396y
  3. Publisher: 2013
  4. Abstract:
  5. 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
  6. Keywords:
  7. Nanomaterial ; Field-effect transistor ; Mobility ; Subthreshold swing ; Trap states ; Density of trap state ; Electronic transport ; Nanocrystal films ; Quantum dot solids ; Trap state ; Voltage breakdown ; Carrier mobility ; Electronic structure ; Field effect transistors ; Gate dielectrics ; Optoelectronic devices ; Semiconductor doping ; Semiconductor quantum dots ; Quantum dot ; Colloidal quantum dots ; Colloid ; Chemistry ; Electron transport ; Equipment ; Equipment failure ; Semiconductor ; Ultrastructure ; Device failure analysis ; Devices ; Colloids ; Equipment Design ; Equipment Failure Analysis ; Materials Testing ; Nanostructures ; Particle Size ; Quantum Dots ; Transistors, Electronic
  8. Source: ACS Nano ; Volume 7, Issue 7 , 2013 , Pages 5757-5762 ; 19360851 (ISSN)
  9. URL: http://pubs.acs.org/doi/abs/10.1021/nn401396y