Surface plasmon coupling effect in an InGaN∕GaN single-quantum-well light-emitting diode

The authors demonstrate the coupling effects between the quantum well (QW) and surface plasmon (SP) generated nearby on the p-type side in an InGaN∕GaN single-QW light-emitting diode (LED). The QW-SP coupling leads to the enhancement of the electroluminescence (EL) intensity in the LED sample designed for QW-SP coupling and reduced SP energy leakage, when compared to a LED sample of weak QW-SP coupling or significant SP energy loss. In the LED samples of significant QW-SP coupling, the blueshifts of the photoluminescence and EL emission spectra are observed, indicating one of the important features of such a coupling process. The device performance can be improved by using the n-type side for SP generation such that the device resistance can be reduced and the QW-SP coupling effect can be enhanced (by further decreasing the distance between the QW and metal) because of the higher carrier concentration in the n-type layer.