title: Multicolor light-emitting diodes based on semiconductor nanocrystals encapsulated in GaN charge injection layers.
abstract: Numerous technologies including solid-state lighting, displays, and traffic signals can benefit from efficient, color-selectable light sources that are driven electrically. Semiconductor nanocrystals are attractive types of chromophores that combine size-controlled emission colors and high emission efficiencies with excellent photostability and chemical flexibility. Applications of nanocrystals in light-emitting technologies, however, have been significantly hindered by difficulties in achieving direct electrical injection of carriers. Here we report the first successful demonstration of electroluminescence from an all-inorganic, nanocrystal-based architecture in which semiconductor nanocrystals are incorporated into a p-n junction formed from GaN injection layers. The critical step in the fabrication of these nanocrystal/GaN hybrid structures is the use of a novel deposition technique, energetic neutral atom beam lithography/epitaxy, that allows for the encapsulation of nanocrystals within a GaN matrix without adversely affecting either the nanocrystal integrity or its luminescence properties. We demonstrate electroluminescence (injection efficiencies of at least 1%) in both single- and two-color regimes using structures comprising either a single monolayer or a bilayer of nanocrystals.
authors.affiliation: Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: Alexander H
authors.initials: AH
authors.lastname: Mueller
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Petruska
authors.forename: Marc
authors.initials: M
authors.lastname: Achermann
authors.forename: Donald J
authors.initials: DJ
authors.lastname: Werder
authors.forename: Elshan A
authors.initials: EA
authors.lastname: Akhadov
authors.forename: Daniel D
authors.initials: DD
authors.lastname: Koleske
authors.forename: Mark A
authors.initials: MA
authors.lastname: Hoffbauer
authors.forename: Victor I
authors.initials: VI
authors.lastname: Klimov
mesh_terms: D003460:Crystallization / Q000379:methods*; D004735:Energy Transfer; D004867:Equipment Design; D005708:Gallium / Q000737:chemistry*; D008027:Light; D008422:Materials Testing; D036103:Nanotechnology / Q000379:methods*; D009584:Nitrogen / Q000737:chemistry; D010777:Photochemistry / Q000295:instrumentation*; D012666:Semiconductors; D013696:Temperature
chemical_list: D005708:Gallium; D009584:Nitrogen