Influence of the quantum-confined Stark effect in an InGaN/GaN quantum well on its coupling with surface plasmon for light emission enhancement

The authors analyze the contribution of the screening of the quantum-confined Stark effect (QCSE) to the emission enhancement behavior in the process of surface plasmon (SP) coupling with an InGaN/GaN quantum well (QW), which is 20 nm away from a Ag thin film that supports the SP. From the measurements of excitation power dependent photoluminescence and time-resolved photoluminescence (TRPL) spectroscopy, and the fitting to the TRPL data based on a rate-equation model, it is found that when the excitation level is high, the QCSE screening effect not only contributes significantly to the emission enhancement but also increases the SP coupling rate because of the blueshift of emission spectrum caused by the screening effect. Therefore, the emission strength from SP radiation, relative to that from QW radiative recombination, increases with the excited carrier density. Also, a saturation behavior of SP-QW coupling is observed from the fitting procedure. (c) 2007 American Institute of Physics.