Tuning carrier mobilities and polarity of charge transport in films of CulnSexS2-x quantum dots

Sergiu Draguta, Hunter McDaniel, Victor I Klimov

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

Functional CISeS QD FETs were demonstrated with fairly high charge carrier mobilities. CISeS QDs were synthesized with 60% Se cations. The absorption onset is characterized by a similar wavelength. To fabricate FETs a heavily doped silicon substrate was used as a bottom gate electrode and a 500 nm layer of SiO2 (dry thermal oxide) provides a low-leakage gate dielectric. Films of CISeS QDs were deposited onto the substrate by spin coating at 2500 rpm. In order to make a consistent QD layer thickness of ?50 nm, 4-5 cycles of spin coating separated by 5 min of annealing of the film at 100°C were repeated. For ligand exchange, a 0.5 mmol solution of the new ligand in methanol was spin coated during each cycle after spin coating QDs. Without any treatments, the as-synthesized QD films are conductive despite the presence of bulky ligands and exhibit p-type transport. The mobility increases after treatment with short EDT molecules that replace the original passivation. Interestingly, the QD treatment with Cd2+ ions changes the nature of charge transport and results in ambipolar behavior for both electrons and holes.

Original languageEnglish
Pages (from-to)1701-1705
Number of pages5
JournalAdvanced Materials
Volume27
Issue number10
DOIs
Publication statusPublished - Jan 1 2015

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ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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