We report high performance transistors with band-like transport in solution-deposited, CdSe quantum dot arrays with room temperature field-effect mobilities for electrons of ~27 cm2/Vs. Mobility values above the Mott-Ioffe-Regal limit with negligible VDS dependence as well as dramatic red-shifts and broadening observed spectroscopically in the quantum dot resonances are consistent with transport in extended states. Annealing of Indium contacts allows for thermal diffusion and doping of the quantum dot arrays, shifting the Fermi energy and providing access to the delocalized bands. Temperature dependent measurements show band-like transport to 220 K, that is further extended to 140 K by reducing traps at the semiconductor-gate dielectric interface using an Al2O3 instead of an SiO2 gate insulator. The use of compact ligands and doping provide a route to high performance, solution-deposited quantum dot electronics and optoelectronics.

Solution-processable high performance thin-film transistors: Band-like transport in strongly-coupled and doped quantum dot solids

244th National Meeting (2012)

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