Probing plasmonic effects in GaAs AlAs core shell nanowires InGaN GaN quantum wells and Si nano crystals with time resolved cathodoluminescence

by Yevgeny Estrin

at Condensed Matter Seminar

Mon, 29 Jun 2015, 11:30
Physics building (#54) room 207

Abstract

The enhancement of the spontaneous emission rate SER for silver gold and aluminum films deposited on three different quantum heterostructures and nanostructures was probed with time resolved cathodoluminescence CL We show that such metal films on i GaAs AlAs core shell nanowires ii InGaN GaN quantum wells and iii multilayer Si nanocrystals SiNCs lead to an increase in the SER which is attributed to the coupling of excitons and surface plasmon polaritons SPPs Exciton SPP coupling for metal coated nanostructures is investigated as a viable option to enhance the SER and to improve the internal quantum efficiency of light emitting devices The CL technique is found to be an ideal method of excitation for metal covered nanostructures which may be opaque to laser light excitation Electron hole pairs were generated in the metal covered samples by injecting a pulsed high energy electron beam through the thin metal films The enhancement of the SER was observed by direct measurements of the changes in the temperature dependent excess carrier lifetime The three chosen plasmonic metals of Ag Au and Al facilitate an interesting comparison of the exciton SPP coupling for metal films that exhibit varying differences between the surface plasmon energy and the excitonic transition energy of the three foregoing material systems A modeling of the temperature dependence of the Purcell enhancement factor Fp included the effects of ohmic losses of the metals and changes in the dielectric properties due to the temperature dependence of i the intraband behavior in the Drude model and ii the interband critical point transition energies which involve the d bands of Au and Ag

Created on 25-06-2015 by Bar Lev, Yevgeny (ybarlev)
Updaded on 25-06-2015 by Bar Lev, Yevgeny (ybarlev)