title: Bragg extraction of light in 2D photonic Thue-Morse quasicrystals patterned in active CdSe/CdS nanorod-polymer nanocomposites.
abstract: In this paper two-dimensional (2D) photonic Thue-Morse quasicrystals (ThMo-PQCs) in active CdSe/CdS nanorod (NR) doped polymer nanocomposites are proposed and experimentally demonstrated. Active PQCs and undoped lattices have been prepared in a one-step fabrication process by an electron beam lithography technique (EBL) and the effects on light extraction and emission directionality are studied experimentally. Vertical extraction of light was found to be strongly dependent on both the geometric parameters of the ThMo-PQCs and the presence of NR dopants. By changing the geometrical parameters of the photonic structures, the resonance peak could be tuned from a narrow bluish green emission at 543 nm up to a red-NIR emission at 711 nm with a full width at half-maximum of 22 nm which is in good agreement with Bragg's diffraction theory and free photon band structure. Angular resolved measurements revealed a directional profile in the far-field distribution with guided mode extraction in both doped and undoped PQCs and an enhancement as high as 6.5-fold in light extraction was achieved in the doped photonic structures. These experimental results indicate the critical role of the CdSe/CdS NRs in improving the light extraction efficiency of 2D ThMo-PQCs for solid-state lighting and lasing.
authors.affiliation: Institute of Cybernetics E. Caianiello of CNR, Via Campi Flegrei 34, 80072 Pozzuoli, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Rippa
authors.forename: Rossella
authors.initials: R
authors.lastname: Capasso
authors.forename: Pasquale
authors.initials: P
authors.lastname: Mormile
authors.forename: Sergio
authors.initials: S
authors.lastname: De Nicola
authors.forename: Marco
authors.initials: M
authors.lastname: Zanella
authors.forename: Liberato
authors.initials: L
authors.lastname: Manna
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Nenna
authors.forename: Lucia
authors.initials: L
authors.lastname: Petti
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D008027:Light; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*; D012031:Refractometry / Q000379:methods*; D012542:Scattering, Radiation; D018036:Selenium Compounds / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D019187:Cadmium Compounds; D046911:Macromolecular Substances; D011108:Polymers; D018036:Selenium Compounds; D013440:Sulfides; C034939:cadmium sulfide; C058667:cadmium selenide