Behaviors of Surface Plasmon Coupled Light-Emitting Diodes Induced by Surface Ag Nanoparticles on Dielectric Interlayers

Enhancement of the Modulation Response of Quantum-Dot-Based Down-Converted Light through Surface Plasmon Coupling

“…Therefore, the response to the excitation switching-off of such a light emitter is expected to be faster. In other words, the MB of such a light-emitting device can be increased through SP coupling [ 41 , 42 , 43 ]. Meanwhile, with the higher decay rate of carrier concentration in a QW under the SP coupling condition, the carrier concentration in the QW becomes lower.…”

“…Among different metals for producing SP coupling, Ag is a good choice for SP coupling in the visible range due to its favored plasma frequency and low dissipation. Deposited Ag NPs on the top surface have been used for demonstrating the SP coupling effects to increase the IQE and MB, and to suppress the efficiency droop effect of an LED [ 41 , 42 , 43 , 44 , 45 , 46 ]. In this regard, a key issue is the distance between the surface Ag NPs and the QWs of the LED.…”

“…It can also be tuned through the change of its surrounding material. For instance, by inserting a thin dielectric layer of a lower refractive index between surface metal NPs and the LED top layer, the SP resonance spectrum can be blue-shifted [ 43 , 45 , 46 , 55 ]. On the other hand, by covering the surface metal NPs with a certain dielectric material, the SP resonance spectrum can be red-shifted.…”

“…In other words, the RC time constant is smaller and the MB is larger in a micro-LED when compared with a regular-size LED. An MB increase induced by SP coupling has been demonstrated [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 41 , 42 , 43 ]. Generally, the increase factor of MB is about the same as that of the square root of PL decay rate, indicating that the key SP coupling to increasing the MB is the enhancement of carrier decay rate in the QWs of an LED.…”

“…The inclusion of red light always results in a smaller mixed-light MB. The LED MBs of hundreds of MHz have been reported when the mesa size is reduced to a few tens of microns for decreasing the RC time constant [ 41 , 42 , 43 ]. Since the modulation response of a converted light follows that of the fundamental LED emission, the MB of a converted light can also reach the level of hundreds of MHz in a micro-LED.…”