American Chemical Society
nl2028848_si_001.pdf (3.68 MB)

Robust, Functional Nanocrystal Solids by Infilling with Atomic Layer Deposition

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journal contribution
posted on 2011-12-14, 00:00 authored by Yao Liu, Markelle Gibbs, Craig L. Perkins, Jason Tolentino, Mohammad H. Zarghami, Jorge Bustamante, Matt Law
Thin films of colloidal semiconductor nanocrystals (NCs) are inherently metatstable materials prone to oxidative and photothermal degradation driven by their large surface-to-volume ratios and high surface energies. The fabrication of practical electronic devices based on NC solids hinges on preventing oxidation, surface diffusion, ripening, sintering, and other unwanted physicochemical changes that can plague these materials. Here we use low-temperature atomic layer deposition (ALD) to infill conductive PbSe NC solids with metal oxides to produce inorganic nanocomposites in which the NCs are locked in place and protected against oxidative and photothermal damage. Infilling NC field-effect transistors and solar cells with amorphous alumina yields devices that operate with enhanced and stable performance for at least months in air. Furthermore, ALD infilling with ZnO lowers the height of the inter-NC tunnel barrier for electron transport, yielding PbSe NC films with electron mobilities of 1 cm2 V–1 s–1. Our ALD technique is a versatile means to fabricate robust NC solids for optoelectronic devices.