Influence of localized surface plasmons on carrier dynamics in InGaN/GaN quantum wells covered with Ag nanoparticles for enhanced photoluminescence

An analysis of the complex mechanisms of enhanced photoluminescence (PL) from InGaN/GaN quantum wells (QWs) by surface plasmon (SP) coupling is reported. Silver nanopartides were deposited on the QWs to generate a wide surface plasmon resonance (SPR) band covering both PL excitation and emission wavelengths. Significant enhancement of the integrated PL intensity, a blue shift of the PL peak wavelength, a suppression of the relative contribution of PL from In-rich quantum dot-like structures, and an increased PL decay time were observed in temperature-dependent and time-resolved PL spectroscopy. In addition to an enhanced radiative recombination rate by resonant coupling the spontaneous emissions to SPs, QW carrier dynamics can be significantly affected by SPR-enhanced, light-induced local fields. The latter occurs because of screening of the quantum-confined Stark effect and the enhanced localization of carriers. (C) 2015 Elsevier Ltd. All rights reserved.