title: Direct Measurement of Single CdSe Nanowire Extinction Polarization Anisotropies.
abstract: The origin of sizable absorption polarization anisotropies (ρabs) in one-dimensional (1D) semiconductor nanowires (NWs) has been debated. Invoked explanations employ either classical or quantum mechanical origins, where the classical approach suggests dielectric constant mismatches between the NW and its surrounding environment as the predominant source of observed polarization sensitivities. At the same time, the confinement-influenced mixing of states suggests a sizable contribution from polarization-sensitive transition selection rules. Sufficient evidence exists in the literature to support either claim. However, in all cases, these observations stem from excitation polarization anisotropy (ρexc) studies, which only indirectly measure ρabs. In this manuscript, we directly measure the band edge extinction polarization anisotropies (ρext) of individual CdSe NWs using single NW extinction spectroscopy. Observed polarization anisotropies possess distinct spectral features and wavelength dependencies that correlate well with theoretical transition selection rules derived from a six-band k·p theory used to model the electronic structure of CdSe NWs.
authors: Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, Indiana 46556, United States.
authors: Matthew P
authors: MP
authors: McDonald
authors: Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, Indiana 46556, United States.
authors: Felix
authors: F
authors: Vietmeyer
authors: Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, Indiana 46556, United States.
authors: Masaru
authors: M
authors: Kuno
keywords: CdSe; absorption; anisotropy; dielectric contrast; extinction; nanowire; polarization; single particle absorption