De Luca, MartaZilli, AttilioFonseka, H. AruniMokkapati, SudhaMiriametro, AntonioTan, Hark HoeSmith, Leigh MorrisJagadish, ChennupatiCapizzi, MarioPolimeni, Antonio2015-03-312015-03-311530-6984http://hdl.handle.net/1885/13124We investigate the absorption properties of ensembles of wurtzite (WZ) InP nanowires (NWs) by high-resolution polarization-resolved photoluminescence excitation (PLE) spectroscopy at T = 10 K. The degree of linear polarization of absorbed light, ρ(abs), resulting from the PLE spectra is governed by a competition between the dielectric mismatch effect and the WZ selection rules acting differently on different optical transitions. These two contributions are deconvoluted with the help of finite-difference time-domain simulations, thus providing information about the symmetry of the three highest valence bands (A, B, and C) of WZ InP and the extent of the spin-orbit interaction on these states. Moreover, ρ(abs) shows two characteristic dips corresponding to the two sharp A and B exciton resonances in the PLE spectra. A model developed for the dip in A provides the first experimental evidence of an enhancement in the dielectric mismatch effect originating from the Coulomb interaction between electron and hole.M.D.L., M.C., and A.P. acknowledge funding by Sapienza Università di Roma under the “Avvio alla Ricerca 2014”, “Ateneo 2012”, and “Ateneo 2013” grants, in that order. The Australian authors acknowledge the Australian Research Council for financial support. L.M.S. acknowledges funding by the National Science Foundation through NSF DMR-1105362.8 pages© 2015 American Chemical Societyinp nanowiresdielectric mismatchexcitonsphotoluminescence excitationwurtzite band structure2015-01-0910.1021/nl50383742015-12-10