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

Abstract

The authors demonstrate the coupling effects between the quantum well ͑QW͒ and surface plasmon ͑SP͒ generated nearby on the p-type side in an InGaN / GaN single-QW light-emitting diode ͑LED͒. The QW-SP coupling leads to the enhancement of the electroluminescence ͑EL͒ 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 metal͒ because of the higher carrier concentration in the n-type layer.

Enhanced light extraction from InGaN/GaN quantum wells with silver gratings

“…[2][3][4][5] One of them consists in using metallic structures to enhance the radiative rate thanks to the surface plasmons they support. 6,7 These plasmon modes have a high local density of states, and consequently catch the main part of the emission, which can then be coupled to radiative light with a corrugation (either periodic 6 or not 8,9 ). Luminescence enhancements of up to 15 have been demonstrated with these processes.…”

Enhanced internal quantum efficiency of an InGaN/GaN quantum well as a function of silver thickness due to surface plasmon coupling

“…The increasing blue shift is due to the change in shape and thickness of Ag film, which leads the SP energy to a value close to, yet still higher than, the excitonic energy. [8] As the coupling strength increases, the excitonic radiative recombination energy shifts to a slightly higher value [9].…”

Enhancements of emission rates and efficiencies by surface plasmon coupling

“…Quite recently a few groups reported about the SP enhanced LEDs based on our technique [12,13]. However, a Tuning of the SP coupling conditions by choosing the appropriate metal, metal mixture alloys, or several metal nanostructures is also now in progress.…”